Mark the letter A, B, C, or D to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.

We greatly respect  my teacher for all of the best things that she brought to us.

A. look up to

B. look forwards

C. look for

D. look down on

Trong không gian Oxyz, mặt cầu x 2 + y 2 + z 2 + 2 x - 4 y - 2 z - 3 = 0  có bán kính bằng:

A. 9

B. 3

C. 3 3

D. 3