The Normal Range for a White Blood Cell Count Is $3$

The normal range for a white blood cell count is 2,000 cells/?l to 18,000 cells/?l. Write these numbers in scientific notation.

A) 2 × 10 $3$ cells/?l to 1.8 × 10 $5$ cells/?l
B) 2 × 1 $3$ 0 $4$ cells/?l to 1.8 × 10 $4$ cells/?l
C) 2 × 10 $5$ cells/?l to 1.8 × 10 $3$ cells/?l
D) 2 × 10 $3$ cells/?l to 1.8 × 10 $4$ cells/?l
E) 2 × 10 $4$ cells/?l to 1.8 × 10 $3$ cells/?l