(A) for four reasons.
1. Rival for... is idiomatic.
2. Could correctly demonstrates the proper modal of possibility.
3. Active voice.
4. Most concise.
Yes. I simply replaced rival
193. Byron possessed powers of observation that would have made him a great anthropologist and that makes his letters as a group the rival of the best novels of the time.
(A) makes his letters as a group the rival of
(B) makes his letters as a group one to rival
(C) makes his letters a group rivaling
(D) make his letters as a group the rival of
(E) make his letters a group which is the rival of
Just to let people know that the OA is (D), which means "rival of" must also be idiomatic