Answer:
B) vertical stretch
Step-by-step explanation:
Given that the cost of manufacturing x refrigerators is given by the function .
Now it says that the cost doubles for the year 2011 owing to higher raw material prices. So that means cost function will change from f(x) to 2f(x).
Now we need to decide the type of transformation from f(x) to 2f(x).
Remember that when f(x) changes to a*f(x) where value of "a" is greater than 1 then it stretches the function vertically by factor of "a".
in 2f(x), we have a=2
So that means "B) vertical stretch" is the correct choice.