Answer:
A x >= 0
Explanation:
a function is a defined mathematical operation (or a sequence of operations) that uses input values (typically called "x") and calculates the corresponding results (typically called "y").
so, y = f(x)
and (x,y) are then usually the coordinates on the grid.
the domain is the range or interval of numbers the function is using (x) to create results (y).
so, look at the graph !
for what values of x do you see the functional line drawn ?
that means, the functional line goes along only what part of the x-axis ?
I see it starts at x=0 and then continues all the way to the right and clearly further.
for me that means f(x) calculates values for every positive x we can think of. and including 0.
it does not do anything for any negative x-values.
so, clearly answer A (x>=0) is right.