[tex]\qquad\qquad\huge\underline{{\sf Answer}}♨[/tex]
Let the total money earned be x
since each of them get equal share, therefore :
[tex]\qquad \tt \dashrightarrow \:5 \times 30 = x[/tex]
[tex]\qquad \tt \dashrightarrow \:x = \$150[/tex]
And here, we used Total earning as the variable in the problem ~
So, correct choice is D
Total persons including Mary=4+1=5
Earnings per person =$30
Total earnings
Option D