Enzymes used in the lagging strand and leading strand during DNA replication?'

Which one the following enzymes is used in the synthesis of the LAGGING STRAND but is NOT used in the synthesis of the LEADING STRAND?
A. primase.
B. DNA polymerase I.
C. sliding Clamp.
D. DNA Polymerase III.
E. the synthesis of the lagging strand and the leading strand require the same enzymes.

I thought the answer was B, as during replication DNA pol III does all the work on the 5' to 3' end strand, while DNA pol I helps the 3' to 5' strand by removing the RNA nucleotides the RNA primer left behind? Does this also occur on the leading strand? Is this because there is also an RNA primer on the leading strand?