A Table Saw Cuts Construction Studding $\frac { 1 } { 0.5 \sqrt { 2 \pi } }$

A table saw cuts construction studding. Observation has shown that the lengths of the studs are normally distributed with a mean of 10 feet and a standard deviation of 6 inches. Which of the following correctly represents the probability that a randomly chosen stud exceeds 11 feet?

A) $\frac { 1 } { 0.5 \sqrt { 2 \pi } }$ $\int _ { 11 } ^ { \infty } e ^ { ( - 1 / 2 ) [ ( x - 10 ) / 0.5 ] ^ { 2 } } d x$
B) $\frac { 1 } { \sqrt { \pi } }$ $\int _ { 9.5 } ^ { 10.5 } e ^ { - [ ( x - 10 ) / 5 ] ^ { 2 } } \mathrm { dx }$
C) $\frac { 1 } { \sqrt { 2 \pi } }$ $\int _ { 9.5 } ^ { 10.5 } e ^ { - x ^ { 2 } / 2 } d x$
D) $\frac { 1 } { \sqrt { 2 \pi } }$ $\int _ { 11 } ^ { \infty } e ^ { - x ^ { 2 } / 2 } d x$
E) none of these