A company manufactures computers. Function N represents the number of components that a new employee can assemble per day. Function E represents the number of components that an experienced employee can assemble per day. In both functions, t represents the number of hours worked in one day. N(t)=50t/t+4
E(t)= 70t/t+3

Which function describes the difference of the number of components assembled per day by the experienced and new employees?
A. D(t)= 10t(2t+13)/t+3
B. D(t)= 10t(2t+13)/ (t+4)(t+3)
C. D(t)= 10t(2t-13)/t+4
D. D(t)=10t(2t-13)/ (t+4)(t+3)