Express as the Logarithm of a Single Expression $$\log _ { b } c - \log _ { b } d$$

Multiple Choice

Express as the logarithm of a single expression. Assume that variables represent positive numbers.
- $$\log _ { b } c - \log _ { b } d$$

A) $\log _ { b } ( c - d )$
B) $\log _ { b } \frac { d } { c }$
C) $\log _ { 2 b } \frac { c } { d }$
D) $\log _ { b } \frac { c } { d }$