Jim Cramer Answers Twitter (TWTR) Questions on Tesla (TSLA), Tekmira (TKMR), Alcoa (AA) and SolarCity (SCTY)

NEW YORK (TheStreet) -- TheStreet's Jim Cramer answers Twitter  (TWTR) questions from the floor of the New York Stock Exchange, and this week's first question deals with Tesla  (TSLA), which received an upgrade from Deutsche  (DB) on Monday.

Cramer says investors must stay long on Tesla. If Deutsche is right, which Cramer thinks they are, then the scale and profit here are much bigger than he thought. Cramer believes Deutsche's upgrade to "buy" with a $310 price target will move the stock substantially, so he would not sell it.

The next question asks for Cramer's pharma plays given the ongoing Ebola issue, and he notes investors have driven up Tekmira Pharmaceuticals  (TKMR), a smaller company. He thinks people keep shorting it and expecting it to go down, but says the stock will obviously soar if the company has an Ebola cure. Cramer thinks the trade has been done and would take profits on the stock.

Must Watch: Cramer Answers Twitter Questions About Tesla's Upgrade, SolarCity

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Another user asks if  Alcoa  ( AA) is still a good stock for the long term. Cramer notes the stock has doubled in the last year, and stocks usually consolidate after they double. He thinks it could go down before it goes up, but he thinks the company has made a major turn, as has the price of aluminum. Therefore, he tells investors not to sell Alcoa.

Asked about SolarCity's  (SCTY) recent quarter and its potential for the next quarter, Cramer refers to TheStreet's Herb Greenberg. He wrote the company had a decline in cash flow and did not seem to care about the cash flow at all when the stock was flying, which means investors should be cautious. Cramer agrees with Greenberg and says SolarCity is not for him.

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