If the stock price increases dramatically, the most profitable strategy among the choices is the one that benefits from a strong rise in the underlying.

A bull spread with puts is a bullish strategy using puts, typically constructed as:

• short higher-strike put
• long lower-strike put

When the stock rises substantially, both puts expire worthless, so the trader keeps the net credit received initially.

The other strategies are not favored by a large upward move:

• Bear spread with puts benefits from falling prices.
• Butterfly spread with calls profits most when the stock ends near the middle strike.
• Calendar spread with calls is typically best when the stock is near the strike at the short option’s expiry.

Therefore, the most profitable strategy is A. Bull spread with puts.