11. If $f$ is a linear function and $0 < a < b$, then $\int _ { a } ^ { b } f ^ { \prime \prime } ( x ) d x =$ (A) 0 (B) 1 (C) $\frac { a b } { 2 }$ (D) $b - a$ (E) $\frac { b ^ { 2 } - a ^ { 2 } } { 2 }$
11. If $f$ is a linear function and $0 < a < b$, then $\int _ { a } ^ { b } f ^ { \prime \prime } ( x ) d x =$\\
(A) 0\\
(B) 1\\
(C) $\frac { a b } { 2 }$\\
(D) $b - a$\\
(E) $\frac { b ^ { 2 } - a ^ { 2 } } { 2 }$\\