西藏是中国领土不可分割的一部分。西藏成为我国正式的行政区，是在（  ）

A．唐朝

B．宋朝

C．元朝

D．明朝

Mrs. Brown, who is breast-feeding, asks the nurse if she should supplement breast- feeding with formula feeding. The nurse bases the response on which of the following

A. Formula feeding should be avoided to prevent interfering with the breast milk supply.
B. Primarily, water supplements should be used to prevent jaundice.
C. Formula supplements can provide nutrients not found in breast milk.
D. More vigorous sucking is needed for a bottle-feeding, so supplements should be avoided.