Explanation

A stop-loss sell order at $30 best meets the dual objectives because:

1. Retains ownership during price increases: The stop-loss order only triggers when the stock price drops to $30, allowing the investor to continue holding the stock as long as it's going up

2. Exits position on price decline: Once the stock drops to $30, the stop-loss order becomes a market order and executes at the best available price, completely exiting the position

Why other options don't work:

• A. Sell market order: Would execute immediately at current price, not allowing for potential upside
• B. Sell limit order at $37: Would only execute if price reaches $37 or higher, but provides no protection if price drops below $30
• D. Stop-and-limit sell order at $30: May not execute if market gaps below $30, potentially leaving the position exposed to further losses

The stop-loss order provides the automatic exit protection while allowing unlimited upside potential.