Pls next time complete your question
Answer:
C. have been walking
Explanation:
A is talking in past tense and B also has a past tense vibe.
#1 : A. meanings of collective nouns
#2: (I am not too sure about this one but i think it's either A or C
#3: B. Define
#4: Some of these nouns are pretty amusing
Sorry for being 3 days late :(
