Express as the Logarithm of a Single Expression $\log _ { 5 } 9 - \log _ { 5 } 10$

Multiple Choice

Express as the logarithm of a single expression. Assume that variables represent positive numbers.
- $\log _ { 5 } 9 - \log _ { 5 } 10$

A) $\log _ { 10 } \frac { 9 } { 10 }$
B) $\log _ { 5 } - 1$
C) $\log _ { 5 } \frac { 10 } { 9 }$
D) $\log _ { 5 } \frac { 9 } { 10 }$