Substitute to Find the Value of the Expression $r$ Kilometers Per Hour For

Substitute to find the value of the expression.
-Traveling at $r$ kilometers per hour for $t$ hours, a driver will travel $r t$ kilometers. How far will Danny travel in 16 hours at a speed of 99 kilometers per hour?

A) $115 \mathrm{~km}$
B) $1584 \mathrm{~km}$
C) $6.2 \mathrm{~km}$
D) $1584 \mathrm{mi}$