HELP PLEASE!!

The cost of the dress shirt that Mindy bought was $2 more than half the cost of the pair of slacks she purchased.

If Mindy spent $21 on the dress shirt, what was her cost for the slacks?

A. $38.00
B. $9.50
C. $46.00
D. $11.50
E. $19.00

I'm stuck between D and E.