In the following one-word substitution question related to finance and trading, select the term that means to sell stocks, securities, or commodities in advance of acquiring them, with the aim of making a profit when the price falls.

Introduction / Context:
This question checks your knowledge of a specific financial term widely used in stock markets and trading. The phrase describes the act of selling stocks or other securities before actually owning them, with the expectation that their price will fall and they can be bought back later at a lower price. This practice is very common among traders and is known by a particular one-word term in English financial vocabulary.

Given Data / Assumptions:

• The action described is selling before buying.
• The aim is to profit when the price of the asset falls.
• The context is clearly financial, related to stocks, securities, or commodities.
• We need the standard technical term used by traders.

Concept / Approach:
In stock market terminology, this practice is called "short selling", and the verb form commonly used is "to short" or "shorting" a stock or security. The trader borrows the shares, sells them at the current price, and hopes to buy them back later at a lower price to repay the borrowed shares and keep the difference as profit. The other options in the question are general words related to cheating or fraud, but they are not technical trading terms and do not specifically describe this legal, though risky, financial strategy.

Step-by-Step Solution:
Step 1: Identify that the description involves selling something you do not yet own. Step 2: Note the goal: to benefit when the price goes down later. Step 3: Recall the standard market term "short selling" and its verb form "shorting". Step 4: Compare the options: only "shorting" is a recognised financial term that exactly matches this behaviour. Step 5: Confirm that the remaining words are more general and relate to deception, not specifically to this trading strategy.

Verification / Alternative check:
You can verify this meaning by thinking of financial news headlines such as "Traders are shorting the stock" or "He made money by shorting the market." In each case, the trader expects prices to fall. Financial textbooks, business newspapers, and investment websites all use "shorting" in this way. The other terms in the options list are rarely, if ever, used in serious financial writing to describe a legitimate trading move.

Why Other Options Are Wrong:
Option a: "bilking" means cheating someone out of money, usually by fraud, not a technical market strategy involving price movements. Option b: "duping" means deceiving or tricking someone, again unrelated to the formal practice of selling borrowed shares. Option c: "conning" is informal slang for cheating or tricking another person, which is not the precise concept described in the question.

Common Pitfalls:
A frequent error is to choose a word that sounds related to money or cheating without recognising whether it is a specialised term or everyday slang. Remember that exam questions on one-word substitutions usually expect a precise, standard expression rather than casual or emotional words. Focus on the technical description given in the question and match it with the correct financial vocabulary.

Final Answer:
The correct one-word substitution is shorting.