Correct Answer: Convoluted

Solution : The first option is correct.

In the sentence, the term complex describes the intricate and involved nature of the physics of laser-driven fusion. Similarly, convoluted refers to something that is extremely complex, intricate, or difficult to understand due to its intricate twists and turns.

The meanings of the other options are as follows:

• Streamline means to simplify or make a process more efficient.
• Simplified means something made easier to understand or less complex.
• Modest means something with simplicity and humility.

Therefore, the correct answer is convoluted .