Sentence Correction

Q. Although Napoleon's army entered Russia with far more supplies than they had in their previous campaigns, it had provisions for only twenty-four days.
(A) they had in their previous campaigns
(B) their previous campaigns had had
(C) they had for any previous campaign
(D) in their previous campaigns
(E) for any previous campaign


I understand the OA is E on the basis of pronoun antecedent but want to know the ans on the basis of comparison signaled by than. Can someone help with the comparison here?

Although Napoleon's army entered Russia with far more supplies than they had in their previous campaigns, it had provisions for only twenty-four days.

(E) for any previous campaign

Army is singular hence "they/ their" is wrong hence E is the only one left. Also the non underlined part directs the use of "IT".
it is comparing correctly the supplies
previous and the new one.

Please underline the part under study, before you post!

Thanks,
GK

Although Napoleon's army entered Russia with far more supplies than they had in their previous campaigns, it had provisions for only twenty-four days.

(A) they had in their previous campaigns
(B) their previous campaigns had had
(C) they had for any previous campaign
(D) in their previous campaigns
(E) for any previous campaign