The given expression is in log 5
We need to convert it to log 10 by applying the change of base formula which is expressed as
logb a = logc a/logc b
By comparing with the given expression,
b = 5, a = 121, b = 10
We don't need to write base 10 because all logs are to base 10 unless stated otherwise. Thus, we have
log5 121 = log 121/log 5
= 2.979792
Rounding to the nearest thousandth, it is
2.980
Option B is correct