Answer:
Option
c
Step-by-step explanation:
Given that the quantity decreases at a rate that is proportional to the current value of the quantity.
This can be expressed as
rate of change of y = derivative of y
=y'=-ky
where k is the constant of proportionality
This differential equation is linear and can be solved by separation of variables

Integrate both sides

Rise to power e

where A=e^C
Hence this is exponential decay