In parallelogram A B C D, \overline{D E} is the altitude to the base \overline{A B} and \overline{D F} is the altitude to the base \overline{B C}. [Note: Both pictures represent the same parallelogram.] If D C=12, E B=4 and D E=6, then D F=
Answer Choices
A. 6.4
B. 7
C. 7.2
D. 8
E. 10