问一题数学，PREP上的

茶色的秋天

If n and t are positive integers, what is the greatest prime factor of the product nt?
  (1) The greatest common factor of n and t is 5.
  (2) The least common multiple of n and t is 105.
答案是B，为什么啊。我选的D

socialelite

1 不行啦，比如t=5*13, n=5*11, 5是最大公倍数