The graph of the cubic function f is shown in the xy-plane above. If f (a) = 0, where a is a constant, what is one possible value of a?

The correct answer is: 8

Hint:
The concept used in this question is concept of functions.
Functions are relations where for each input there is particular output.
Functions are represented by f(x).
Point at which graph cut x-axis are roots of equation.
Step by step explanation:
Given:
Graph cut x-axis at points x = 2, x = 4 and x = 8.
Step 1:
Points at which graph cut x-axis are roots of function.
∴ function has three roots
⇒ it is cubic equation.
Step 2:
This points satisfy the equation and when put in the equation gives zero.
∴ f(2) = 0
f(4) = 0,
f(8) = 0