For every real number $x$, the number $A$ is defined as
$$\sum _ { k = 2 } ^ { 4 } \cos ( 2 k x ) = A$$
Accordingly,
$$\sum _ { k = 2 } ^ { 4 } \cos ^ { 2 } ( k x )$$
What is the equivalent of the expression in terms of A?\
A) $A + 2$\
B) $A + 4$\
C) $\frac { \mathrm { A } + 1 } { 2 }$\
D) $\frac { A + 2 } { 2 }$\
E) $\frac { A + 3 } { 2 }$