Which of the following is NOT a type of order that can be placed in the stock market?

The selection of "C. Prompt orders" as the answer highlights that this term does not represent an established type of order in the stock market. Market orders, limit orders, and stop-limit orders are all recognized types of trading instructions that investors can use.

Market orders are executed at the current market price, ensuring quick execution but without price guarantees. Limit orders allow investors to specify the maximum price they are willing to pay for a security or the minimum price they are willing to accept when selling, providing more control over the transaction price. Stop-limit orders are a combination of stop orders and limit orders, enabling a trader to specify a stop price at which the order becomes a limit order, allowing for strategic control in volatile markets.

In contrast, "prompt orders" is not a terminology used in stock trading. It's essential to understand the various order types, as they reflect different strategies and objectives in market transactions. Therefore, recognizing the absence of "prompt orders" in the lexicon of trading orders reinforces the understanding of recognized trading practices.