GMAT Sentence Correction (SC) | Re: A delegation of 60 farmers called on the chief minister so

I do not see a problem with A - "so as to" is alright.

The construction is correct. Two verbs can be made parallel using a conjunction. (I read and write. ..correct - similarly,A delegation called on and pleaded .. grammatically correct)

"Its" (referring to delegation) is better than "their" (referring to farmers).