Which of the following occurs as electrons are passed to various proteins through the electron transport chain [in the light-dependent reaction]? A. Two hydrogen ions are bound to a free oxygen ion, generating a molecule of water.
B. They attach to NADPH, forming NADP+.
C. An electrochemical gradient of protons across the thylakoid membrane is established.
D. They are boosted to an even higher energy level.

An electrochemical gradient of protons across the thylakoid membrane is established.

Explanation:

evidence and logical support is essential for a scientist to do in order to maintain credibility. this is because no one can believe without any logic and without any evidence.hence a scientist can maintain credibility by proving himself and by answering logically so experiments prove very beneficial. logical hypothesis give conclusion which is acceptable. therefore, there are two main factors to maintain credibility by a scientist is evidence and logical support.