IBPS Clerk Prelims 7-Dec-2019 Paper

In each question, one sentence is given. In each sentence, certain words are in bold and numbered from A to D. Below the sentences are given five options with possible pairs of interchange of those bold words. Choose the pair(s) of words that need to be interchanged to make the sentence grammatically correct and meaningful.
The Silk Road not only (A)credited as a major trade route (B)from India and China but is also (C)served for facilitating the spread of Buddhism (D)between India to East Asia.