Evaluate or Simplify the Expression Without Using a Calculator $R = \log \left( \frac { a } { T } \right) + B$

Multiple Choice

Evaluate or simplify the expression without using a calculator.
-Use the formula $R = \log \left( \frac { a } { T } \right) + B$ to find the intensity $R$ on the Richter scale, given that amplitude a is 431 micrometers, time T between waves is $2.4$ seconds, and B is $2.4$ . Round answer to one decimal place.

A) $4.7$
B) $7.6$
C) $2.3$
D) $9.3$