Find the Missing Dimension of the Shaft in the Illustration $8 \frac { 1 } { 4 }$

Multiple Choice

Find the missing dimension of the shaft in the illustration.

A) $8 \frac { 1 } { 4 }$ in.
B) $8 \frac { 1 } { 2 }$ in.
C) $7 \frac { 1 } { 4 }$ in.
D) $7$ in.
E) 8 in.