1公升的红茶加12公克的糖最好喝，那请问几公升的红茶加20公克的糖最好喝？

—Did Mr White tell you _______?

—Yes. He said he went there in 2003. [ ]

A. when he traveled to Tibet

B. how he goes to Wuhan

C. where he spent his holidays

D. why did he visit Kunming