Long Call
The strategy
A long call gives you the right to buy the underlying stock at strike price A.
Calls may be used as an alternative to buying stock outright. You can profit if the stock rises, without taking on all of the downside risk that would result from owning the stock. It is also possible to gain leverage over a greater number of shares than you could afford to buy outright because calls are always less expensive than the stock itself.
But be careful, especially with short-term out-of-the-money calls. If you buy too many option contracts, you are actually increasing your risk. Options may expire worthless and you can lose your entire investment, whereas if you own the stock it will usually still be worth something. (Except for certain banking stocks that shall remain nameless.)