Twelve fish were introduced into a large lake. In 3 years, the population has multiplied by a factor of 20. If P is the number of fish t years after introduction, which formula relates P and t?
a) P = 12 * 3²⁰
b) P = 12 * 20³
c) P = 12 * 20ᵗ
d) P = 12 * t²⁰
