Answer:
Smh. This is kinda late, but hope this helps.
Explanation:
The enzyme DNA polymerase catalyzes the formation of sugar phosphate units along the side of the "ladder". The sugar phosphate units connect one base pair/rung on the ladder to the next one.
Therefore our answer is :
A) DNA polymerase joins individual nucleotides together to form a new complementary strands of DNA. :)