Let $f ( x ) = \sqrt { x - 1 }$

Multiple Choice

Let $f ( x ) = \sqrt { x - 1 }$ on $[ 1,3 ]$ Then the set of all c in (1,3) guaranteed by the Mean Value Theorem is

A) $\left\{ \frac { 5 } { 4 } \right\}$
B) $\left\{ \frac { 9 } { 8 } \right\}$
C) $\left\{ \frac { 3 } { 2 } \right\}$
D) $\{ 2 \}$
E) $\left\{ \frac { 5 } { 2 } \right\}$