Answer
graph A
Work Step by Step
For simple interest}
$INT=PVrt$,
$FV-PV=PVrt$,
$FV=PVrt-PV$,
PV is constant and r is constant, so
$FV$, as a function of time, is a linear function
(with PV as y-intercept and $PV\cdot r$ as slope).
Of the offered, only graph A is linear.
