NEW YORK (TheStreet) -- As usual, Jim Cramer's Twitter (TWTR) - Get Twitter, Inc. Report questioners had questions on Monday about on investing specific stocks. But he started off with one that took a wider view: Why, he was asked, do investors follow the Dow Jones Industrial Average anymore, as opposed to looking only at the S&P 500 and Nasdaq?

You can look at any index you want, Cramer replied, though he pointed out that the S&P's trading at a higher valuation than the Dow. He also said investors don't have faith in last week's rally, and given the market's volatility, they shouldn't.

In response to the viewer who wondered if Alcoa (AA) - Get Alcoa Corp. Report was a value trap or a great value, Cramer said that it's a good company that's fallen 40%. "It's typical of what I'm saying. It's in a total bear market as if nothing good has happened, and many good things have happened," said Cramer.

Another viewer asked for Cramer's take on HCA Holdings (HCA) - Get HCA Healthcare Inc (HCA) Report , and he responded that it's a stock that makes sense. It had a major breakdown last Monday, came back from the losses well, and is in bull-market mode.

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Asked about Citigroup (C) - Get Citigroup Inc. Report, Cramer responded that all the money center banks are in free fall, including Morgan Stanley (MS) - Get Morgan Stanley (MS) Report, which is a holding of Action Alerts PLUS, the portfolio he manages. Cramer said for the year, Citigroup is unchanged, but it could be impacted by a Federal Reserve interest rate increase. He said if the rate hike comes, Citigroup's numbers will be cut and people will want to buy the stock in the $40s.

Another viewer asked whether American Airlines (AAL) - Get American Airlines Group, Inc. Report is a hold or sell. Cramer responded that Delta (DAL) - Get Delta Air Lines, Inc. Report is down 10% and he thinks it's cheaper than American.

Finally, another viewer asked whether Fitbit (FIT) - Get Fitbit, Inc. Class A Report and Apple (AAPL) - Get Apple Inc. (AAPL) Report watch are targeting different users entirely. Cramer pointed to a recent survey that shows they are targeting the same users, and he thinks the second version of the Apple watch will be much more savvy about athletics. He added that Fitbit should team up with Nike (NKE) - Get NIKE, Inc. (NKE) Report or Under Armour (UA) - Get Under Armour, Inc. Class C Report, noting that the stock hit his $50 price target but has not offered additional clarity. "In this market, which is a bear market,  you need clarity. You can't just come out and say trust us, because no one is trusting anyone," said Cramer.

Send your Twitter questions to @jimcramer, using #CramerQ.

At the time of publication, Jim Cramer's charitable trust Action Alerts PLUS held MS.