Aye

what is the domain of the step function f(x) = ⌈2x⌉ – 1?

a.{x| x ≥ –1}

b.{x| x ≥ 1}

c. {x| x is an integer}

d. {x| x is a real number}

The biggest possible set is .

The question to ask yourself is: is the operation  not valid for some values of x ? ("not valid" = impossible to compute)
After removing all invalid values of x (if any), you have obtained the domain.