Scientists have determined that the inner ear assists in awareness of body orientation,
since people with disorders of the inner ear were found to have increased
difficulties in maintaining balance.
(A) were found to have increased difficulties
(B) have been found to have increased difficulty
(C) were found to have increasing difficulty
(D) had been found to have increased difficulties
(E) have been found to have increasing difficulties

my doubt: i am not able to understand as how B can be correct here? choice B is using "present perfect" with "present perfect infinitive"