If the government deregulates the airline industry then:

If the government deregulates the airline industry then less competition will be expected.

Bigger airlines will be able to offer more services to the public to the detriment of smaller airlines. Which may result to the bankruptcy of the smaller airlines or let smaller airlines merge with each other to compete with bigger airlines. Bigger airlines may also purchase by other airlines which ultimately result to a decrease in number of competing airlines.

If the government deregulates the airline industry then "b. producerswill have more control over the price charged for their product." Perfectly competitive markets are almost impossible. 

Your answer is d)magnesium