Solve the Problem $S ( t )$ (In $\$ 1000 ) t$

Multiple Choice

Solve the problem.
-After a new product is launched the cumulative sales $S ( t )$ (in $\$ 1000 ) t$ weeks after launch is given by:
$$S ( t ) = \frac { 64 } { 1 + 8 e ^ { - 0.47 t } }$$
What is the limiting value in sales?

A) $\$ 8,000$
B) $\$ 64,000$
C) $\$ 6,000$
D) $\$ 47,000$