The Dormant Commerce Clause is found in what location in the Constitution?

Bubba-Gump Shrimp catches shrimp in Mississippi and ships their catch to a canning facility in Louisiana. Bubba-Gump Shrimp has become so successful and is exporting so much shrimp for canning purposes that the canning industry in Mississippi is starting to dwindle. In response to this local economy-threatening issue, the Mississippi legislature passes a law which "for purposes of protecting the public's health" forbids the transport of shrimp out-of-state except in canned form. The law is invalid primarily because:

The Mississippi legislature is at a loss for how to prevent Bubba-Gump Shrimp from putting all the local canneries out of business, and decides to buy the company at a premium and operate it themselves. When the state takes over the operation they advertise locally for canneries to submit bids based on which contracts will be made. Although three out-of-state canneries who have been doing the canning for Bubba-Gump for the past three years submit bids which were significantly lower than the local bids, even after factoring in the cost of transportation, the state decides to award the canning contracts to two local businesses. The out-of-state companies sue, claiming a Commerce Clause violation. What is the result?

What is the term which means that a federal law, by its very terms, precludes the states from passing laws in conflict with the federal law?

Massahampshire's milk industry has been slowly declining over the past few years. The state legislature, in an effort to boost local milk sales, passes a law requiring local companies charge thirteen-cents per gallon less for their milk than the prices established by federal law. The plan works and local milk companies once again thrive. Is the state law valid?

Westernstate drivers are sick and tired of being temporarily blinded by water splashed on their windshields from the tires of passing trucks. The state legislature commissions a study which finds that the mud guards most commonly used are inadequate, and that circular guards would solve the problem. Despite the fact that most states require trucks to use rectangular guards, the Westernstate legislature passes a law requiring all trucks use the circular guards at all times within Westernstate. This requires truck drivers to pull over at the border upon entering the state to put on the circular guards, and again when leaving to replace the rectangular guards. Can the Commerce Clause be used to stop this madness?

Northernstate was traditionally known as a manufacturing state, but in recent years the industry has shifted to other areas of the country. In order to attract manufacturers back to the nearly abandoned towns of the state, the legislature decides to grant all in-state manufacturers an exemption from collecting and paying sales tax for the next 2 years. The plan works and towns like River Falls are soon thriving again. An out-of-state manufacturing company, F.R. Paper, which sells a large portion of its product within Northernstate applies for the exemption and is denied, at which point they file suit. Claiming discrimination against out-of-staters, F.R. Paper cites the Commerce Clause and argues that Northernstate is illegally discriminating against them. What is the likely result?