If the DNA molecule above were the parent strand of DNA, when the strands are split for replication, which strand would be the template for the leading strand? Why?

The DNA strand having direction 3' to 5' would be used as template strand.

Explanation:

In DNA Replication the strand which is synthesized continuously is known as leading strand while the strand which is synthesized in fragments (okazaki fragements) is called as lagging strand. If one strand of DNA is 3' to 5' other must be in 5' to 3' direction. DNA polymerase can synthesize a strand continuously in only 5' to 3' direction, so the strand having 3' to 5' direction must be used as template to synthesize leading strand (5' to 3').

In other words as DNA polymerase can synthesize a strand continuously in only 5' to 3' direction so the strand having 3' to 5' direction must be used to synthesize leading strand (continuous strand).