A short squeeze occurs when the prices of shares of a specific firm are increasing rapidly, forcing short sellers to closeout their positions. Short selling is a trading strategy where investors sell shares they do not own, with the expectation that the price will fall and they can buy the shares back at a lower price, thereby making a profit. However, if the price of the shares increases instead of falling, the short sellers are forced to buy back the shares at a higher price to close their positions. This buying pressure further increases the price of the shares. This situation, where short sellers are squeezed out of their positions due to rapidly increasing prices, is known as a short squeeze. It is a risky situation for short sellers as they stand to incur significant losses if they are unable to close their positions before the prices rise too high.

Choice A is incorrect. While it is true that a decrease in share prices may encourage more investors to short sell, this does not represent a short squeeze. A short squeeze occurs when the price of an asset increases rapidly, forcing those who have short sold the asset to buy it back at higher prices to cover their positions.

Choice B is incorrect. This scenario describes a situation where there's an oversupply of shares in the market leading to a decrease in price. However, this does not constitute a short squeeze which specifically refers to rapid increase in share prices causing distress for those who have taken short positions.

Choice D is incorrect. This choice simply describes the process of short selling but does not depict a situation of 'short squeeze'. In fact, if the expectation (of purchasing same shares at lower prices) materializes, the short seller would profit, not be squeezed.