Find the Least Common Denominator of the Rational Expressions $\frac { 1 } { 40 x } , \frac { 1 } { 5 x ^ { 2 } }$

Multiple Choice

Find the least common denominator of the rational expressions.
- $\frac { 1 } { 40 x } , \frac { 1 } { 5 x ^ { 2 } }$ , and $\frac { 1 } { 8 x ^ { 3 } }$

A) $40 x ^ { 2 }$
B) $40 x ^ { 5 }$
C) $8 x ^ { 3 }$
D) $40 x ^ { 3 }$