Use Heron's Area Formula to Find the Area of the Triangle

Multiple Choice

Use Heron's area formula to find the area of the triangle pictured below, if $a = 10$ inches, $\mathrm { b } = 12$ inches, and $\mathrm { c } = 4$ inches.

A) $3 \sqrt { 3 }$
B) 20
C) 60
D) $8 \sqrt { 77 }$
E) $3 \sqrt { 39 }$