us to delay handing in
our delaying handing in
our delaying to hand in
us delay to hand in
由题干中的mind可知,后面应当接名词形式,四个选项中BC选项符合这一条件,由delay doing sth可知,只有B选项符合题意。句意:老师不会介意我们推迟交学期论文。