When a right to sell a security is acquired, it is known as __________.

The correct answer is: B. put option.

A put option is a contract that gives the buyer the right, but not the obligation, to sell an underlying asset at a specified price on or before a specified date. The seller of the put option is obligated to buy the asset at the specified price if the buyer exercises the option.

A call option is a contract that gives the buyer the right, but not the obligation, to buy an underlying asset at a specified price on or before a specified date. The seller of the call option is obligated to sell the asset at the specified price if the buyer exercises the option.

A double option is a combination of a call option and a put option. The buyer of a double option has the right to buy or sell the underlying asset at a specified price on or before a specified date. The seller of a double option is obligated to buy or sell the asset at the specified price if the buyer exercises the option.

A single option is an option that gives the buyer the right to buy or sell the underlying asset at a specified price on or before a specified date. The seller of the single option is obligated to buy or sell the asset at the specified price if the buyer exercises the option.