Propose a method to investigate the effect of proton gradient disruption on ATP synthesis in a laboratory setting.

• A. Use an electron transport inhibitor and measure ATP levels before and after its application.
• B. Use a temperature increase and measure ATP levels before and after its application.
• C. Use a light source to stimulate ATP synthesis and measure ATP levels.
• D. Use a proton gradient disruptor and measure ATP levels before and after its application.

Answer: (D)