The keyword here is "IF"
When you suggest something potentially happening in the future - you need the CONDITIONAL form:
You really only have 2 options for PAST framework and 2 options for PRESENT Framework.
We cover this in detail in our Framework #9 (http://www.gmatpill.com/special/verbal/ ... work09.php
If they meet: (PRESENT)
1) they will discuss
2) they will have discussed (grammatically ok, but meaning-wise doesn't really make sense).
If they met: (PAST)
1) they would discuss
2) they would have discussed
The first option you presented:
"a) If X n Y met, they discussed GMAT" - doesn't fit the framework. Because you need a conditional verb tense - you can only go with one of the 4 options presented above. You cannot simply say "If they met, they discussed GMAT" - you need either WILL or WOULD - in there, depending on the verb tense of "meet"
Thanks . I dont have access to the web link you posted. Let me know if it is possible to share the credentials.
Secondly, about the first statement
" If X n Y met, they discussed GMAT " this is a sentence from MGMAT SC
the actual sentence is " If Chris and Jad met, they discussed mathematics"
and explanation says ---The first sentence could be said by someone who is unsure whether Chris and Jad have
actually met: "If this did indeed happen, then that is the consequence."