The correct answer is A.
You have direct variation if x and y are modeled by the equation

In this case, m is the constant of proportionality. So, if the constant has to be 2, the equation becomes

A side note: Actually, option C has a constant of proportionality of two as well, except the roles of x and y are interchanged. I chose option A because usually you want the y = mx form, but the names of the variables are obviously meaningless.
Answer:
x-7>0
Straight answer: x-7
Step-by-step explanation:
Assuming that the timber is X cm long and 7cm was cut off, there remaining amount is x - 7cm. In order for 7cm to be cut off, the timber must have been > 7cm long => x > 7 => x - 7 > 0
It has to be 2.75 as a decimal.