Question

In the following questions, a sentence is divided into four parts in which one of the parts may contain errors. Find out the erroneous part from the given alternatives. If all parts are free from error, choose option E as your answer. (

Q: Answer-In the following questions, a sentence is divided into four parts in which one of the parts may cont...

Rule Parallel structure with correlative conjunctions Not only... but also. Reason Both parts of the pair must join the same part of speech. Here, not only comes before the verb developed, and but also comes before the verb tested. Both sides match perfectly, so there is no grammatical error.