most speakers of General American English, use a vowel closer to [ ɛ ]
,
[Marvin, I just can't agree here.] so why did you decided to switch to #3 instead of #3?
[Did you mean "instead of #2?"] Btw, since you
do have a Western accent, and many Westerners have the CVS, and those
that don't have it seldom notice it in others speech, #1 would also be
acceptable. But for General American, I would say that the best option
is probably #2.
[And I can't agree here, sorry! I think #3 is best (lax e), #1 is OK (lax a),
#2 is the least good (schwa). I'm taking #2 as the case where
"clarity" or "charity" or "hilarity" would nearly rhyme with "purity",
which strikes me as 'way off'.]
Why shouldn't a student use the pronunciation given in the Merriam-Webster Dictionary? (#3).
CJ