妊娠囊孕7周时的直径约为（）。

A.2.0cm

B.3.0cm

C.3.7cm

D.1.0cm

E.4.0cm

You have made a few spelling mistakes in your composition, but it is well written _____.[ ]

A. on a whole

B. as a whole

C. general speaking

D. as the whole