I would say it is B because all the other ones aren’t as logical example A is talking about moving when you can see it’s only mentioned once, so I would say B. Hope this helped
Explanation:
B. losing the support of the Vietcong.
A. to decide, because an infinitive is the word to followed by a verb, in this case decide.
1, We apologise unreservedly for any imputation of incorrect behaviour by Mr Taylor.
2, I could not rest under the imputation.
3, He denied the imputation.
4, The imputation of such benefits raises a number of issues, including the correct identification of the beneficiaries.
For example, “that person in my class has the brand new Playstation. I wish my parents were that rich to buy me one.”