Solve
-Approximately $7 \times 10 ^ { 3 }$ Employees of a Certain Company Average

Solve.
-Approximately $7 \times 10 ^ { 3 }$ employees of a certain company average $\$ 30,000$ each year in salary. What is the total amount earned by all the employees of this company per year? Write your answer in scientific notation.

A) $\$ 21 \times 10 ^ { 9 }$
B) $\$ 21 \times 10 ^ { 8 }$
C) $\$ 2.1 \times 10 ^ { 9 }$
D) $\$ 2.1 \times 10 ^ { 8 }$