Change the Logarithmic Expression to an Equivalent Expression Involving an Exponent

Multiple Choice

Change the logarithmic expression to an equivalent expression involving an exponent.
- $\log _ { \mathrm { b } } 81 = 4$

A) $81 ^ { b } = 4$
B) $81 ^ { 4 } = b$
C) $b ^ { 4 } = 81$
D) $4 ^ { b } = 81$