Question

I neeeeeeeeeedddddddddddd hhhhelpppppp

Answer 1

The step function is characteristic of the floor or ceiling functions, which map a real number to an integer.  There's clearly a factor of 2, indicated by two units of y for every one unit of x.

The open and filled circles indicate, for example, f(1)=2, f(1.01)=4.   That means we're rounding up, so we're using the ceiling function.

$f(x) = 2 \lceil x \rceil$

Answer: second choice