Its in the picture below
a: 1% decay
b: 10% decay
c: 9% growth
d: 90% growth

  b:  10% decay

Step-by-step explanation:

Expressed as a percentage change, the growth is usually the value of the base of the exponential function after 1 has been subtracted. That result is expressed as a percent:

  0.9 - 1 = -0.10 = -10% . . . . . 10% decay

The "t/12" exponent means this is the decay that is experienced over 12 units of time. This might be the annual decay, where t is expressed in months, for example.