The large DNA molecules in human chromosomes take more time to replicate than the smaller, circular bacterial chromosomes. If a 1,000-kilobase (kb) fragment of DNA has 10 evenly spaced and symmetric replication origins, and DNA polymerase moves at 1 kb per second, how many seconds will it take to produce two daughter molecules? (Ignore potential problems at the ends of this linear piece of DN
A:) Assume that the 10 origins are evenly spaced from each other but not from the ends of the chromosome.
选项：

A:20
B:30
C:40
D:50
E:100