We are given log ( 10^3)
We can use one of the properties of logs
log u^n = n log u
Rewriting log ( 10^3) using this property
log ( 10^3) = 3 log 10
log has an implied base of 10
log 10 = 1
3 log 10 = 3 *1 =3
The two correct choices are
A. 3 * log 10
D. 3
