50. Which of the following statements correctly describes the difference between the leading strand and the lagging strand in DNA replication? (A) Both of the leading strand and lagging strand require an DNA primer. (B) The leading strand is synthesized continuously in the 5' →3' direction, while the lagging strand is synthesized discontinuously in the 5'→ 3' direction. (C)The leading strand is synthesized in the 3'→5' direction in a discontinuous fashion, while the lagging strand is synthesized in the 5'→ 3' direction in a continuous fashion. (D) There are different DNA polymerases involved in elongation of the leading strand and the lagging strand.