TOEIC・English Undergraduate about 1 yearago

なぜ()の位置に形容詞の比較級が置かれるのか解説読んでも理解ができなかったので教えて頂きたいです

(22 Hassan Engineering hopes to make partnerships with the contractors 111 -- than they have been to maintain its competitive pricing strategy. (A) stronger (B) strongest (C) more strongly (D) most strongly