We effectively rewrite the equation as
In order for the LHS to be defined, we need to restrict 
, or 
. Now, the LHS will vanish when the numerator is 0, which happens for
This value is indeed smaller than 4, so the solution is 
.
Her credits need to be AT LEAST EQUAL TO OR GREATER THAN 144 (credit hours) so we can eliminate choices B and D.
She already completed 4 semesters in which she receives 15 credit per semester.
This expression can be written as 4(15).
She needs to do a certain remaining hours of credit which can be represented by c and only c without any other coefficient.
So, the most reasonable choice here is A.
c or d for sure hope this helps
