Opportunity cost: value of the best forgone alternative Steps:

• Rank Sam's preferences: first cricket match, second town parade, third cinema.
• Identify cancellations: thunderstorm eliminated cricket match and town parade as options.
• Determine available choices: cinema or alternative uses of time, like free time.
• Conclude forgone option: by selecting cinema, Sam sacrificed his free time.

Why D is correct:

• Opportunity cost is the highest-valued feasible alternative forgone; with preferred events unavailable, free time represents the next best use of his afternoon.

Why the others are wrong:

• A: Cricket match was cancelled, so not a viable alternative.
• B: Town parade was cancelled, so not a viable alternative.
• C: Visiting relatives is not mentioned as an option or preference; not enough information.

Final answer: D