The sentence is grammatically incorrect, at least in American English (which the GMAT uses).
I've come across some sources saying that 'poser' can be synonymous with 'question' in Indian varieties of English. However, even if we replace the word 'poser' with 'question,' the sentence is still incorrect on the GMAT. The following is wrong on the GMAT:
He asked a question what welfare measure he had undertaken.
You'd need to phrase it as 'he asked a question about what welfare measure...' etc.
e: I just realized that you were asking about the meaning, not the grammar! I think the idea is that D. Jayakumar asked Mr. Haasan a question about welfare measures, and that a few days later, Mr. Haasan made the claim described by the sentence.