An automatic investment plan includes a fixed amount of money, specific funds, and regular intervals.

Short interest is the number of shares of the stock that have been sold short and remain unclosed as of the last update. A significant short interest means that bears are attacking the stock price, and the possibility for the stock price to fall is higher. On the contrary, a sharp decrease in short interest means that the short sellers are buying stocks to close positions, which may further increase the stock price.

Short sale data is important in understanding the market sentiment, and high short selling data usually reflects strong bearish sentiment. Investors who like to go long can track short-selling data and avoid stocks whose stock prices may have a downward trend; those interested in short sales can find stocks with a high short-selling ratio and thus investment opportunities.

Short selling means that you expect the price of a security to fall, then you sell some borrowed shares at a higher price, hoping to buy the same number of shares back at a lower price and return them to lenders. If the stock price falls, you will get a profit; but if the stock rises, you will suffer a loss.

to select an appropriate option, you should first consider the option type and the exercise price. A proper call option gives you the right to buy at a lower price if the stock price rises. And the call price rises also, selling it can make a profit. For the exercise price, $350 may be too high, and $300 is more suitable.

Equity represents the shareholders' ownership of a company, which covers a wide range of rights, such as the entitlement to receive dividends, vote, and receive a distribution in liquidation. The equity of all shareholders, which is called shareholders' equity, equals total assets minus total liabilities.

The most commonly used inflation index is the consumer price index (CPI). A high CPI may reflect inflation, in which prices go up across the entire economy. Only when inflation is kept within reasonable limits can the nation keep the economy running smoothly.

An ETF is a type of exchange-traded product that offers investors a way to pool their money in a fund that makes investments in stocks, bonds, or other assets. An ETF is traded on stock exchanges at market price.

The two primary functions of options are hedging risks and using less money to get higher potential returns.
A is not a rational reason why people invest in options.
Options can not change the market operation rules but profit through strategies, so C is incorrect.