A call option gives the holder the right to buy the underlying asset at a fixed strike price until the option expires. A call buyer tends to gain if the underlying rises well above the strike before expiration, and the most a call buyer can lose is the premium paid. This is a plain description of the contract, not a suggestion to trade one.
The app files could not be fetched. This is usually a network hiccup or an out-of-date cached copy of the site.