The correct answer is option 1: increasing the boiling point of water.

A pressure cooker is designed to cook food faster by increasing the boiling point of water. Without a pressure cooker, water boils at 100 degrees Celsius (212 degrees Fahrenheit) at atmospheric pressure. However, inside a pressure cooker, the pressure is increased, which raises the boiling point of water. The increased pressure prevents steam from escaping and allows the temperature inside the cooker to rise above 100 degrees Celsius, resulting in faster cooking times.

By increasing the boiling point of water, the pressure cooker can effectively transfer more heat to the food being cooked. This leads to faster cooking times as the food reaches higher temperatures. The higher pressure also helps in tenderizing the food by breaking down its fibers more quickly.

Option 2, decreasing the boiling point of water, is incorrect. Lowering the boiling point of water would not result in faster cooking but rather slower cooking as it would require less heat to boil the water.

Option 3, increasing the melting point of water, and option 4, decreasing the melting point of water, are not relevant to the cooking process in a pressure cooker.