A mutant of E. coli with a heat-sensitive DNA ligase (25℃ permissive, 37℃ nonpermissive) has been used to show that DNA synthesis is discontinuous. Examination of DNA replication in the presence of [3H]-thymidine in the mutant would demonstrate which of following?

A.The accumulation of short segments of unlabeled DNA at 25℃ and at 37℃.

B.The accumulation of short segments of unlabeled DNA at 25℃ but not at 37℃.

C.The accumulation of short segments of radioactive DNA at 37℃ but not at 25℃.

D.The incorporation of short fragments of radioactive DNA into longer ones at 25℃ and at 37℃.

正确答案：The accumulation of short segments of radioactive DNA at 37℃ but not at 25℃.