(A) has been necessary to develop and enforce the principle that all juries must be -- this is the only option remained and is correct
(B) was necessary for developing and enforcing the principle of all juries being -- being is wrong here
(C) was to be necessary in developing and enforcing the principle of all juries to be -- was to be is wrong
(D) is necessary to develop and enforce the principle that all juries must be -- is necessary is wrong,we are talking about past here
(E) will be necessary for developing and enforcing the principle of all juries being -- will, wrong and being,wrong
(B) was necessary for developing and enforcing the principle of all juries being -- being is wrong here
(C) was to be necessary in developing and enforcing the principle of all juries to be -- was to be is wrong
(D) is necessary to develop and enforce the principle that all juries must be -- is necessary is wrong,we are talking about past here
(E) will be necessary for developing and enforcing the principle of all juries being -- will, wrong and being,wrong