"Oh, Bob, don’t be so silly. You know the dog won’t be __56__ with any medicine." "Oh, he __57 ," replied Bob. Half an hour later, however, Blackie had not returned. Bob felt as if Frank were 58 him and he felt __59__ about it."Something has surely happened to him," said Bob," He never 60 me." Frank smiled. Just then Blackie came in. Frank was surprised to see a bottle of medicine in his mouth.
选项：

A: angry
B: worried
C: afraid
D: anxious