Use the Information Given About the Angle θ, 0 ≤θ $\cos \theta = \frac { 4 } { 5 } , \frac { 3 \pi } { 2 } \leq \theta \leq 2 \pi$

Use the information given about the angle θ, 0 ≤θ ≤ 2π, to find the exact value of the indicated trigonometric function.
- $\cos \theta = \frac { 4 } { 5 } , \frac { 3 \pi } { 2 } \leq \theta \leq 2 \pi$
Find $\cos \frac { \theta } { 2 }$ .

A) $\frac { 2 } { 5 }$
B) $- \frac { 3 \sqrt { 10 } } { 10 }$

C) $\frac { 3 \sqrt { 10 } } { 10 }$

D) $- \frac { 2 } { 5 }$