Topic: Sequence of Tense,

Best Answer Explained in Below-:

The correct option is A) "when I wake up" because it most appropriately conveys the temporal relationship between feeling weak and the action of waking up. The phrase "when I wake up" specifically indicates the moment in time at which the speaker experiences weakness, making it a clear and straightforward expression. This choice also aligns with standard English usage and captures the immediate cause-and-effect relationship between waking up and feeling weak.

Option B) "as I wake up" suggests a simultaneous action but implies a gradual process rather than indicating a specific moment of feeling weak. While it is somewhat acceptable, it doesn’t convey the immediate feeling upon waking as clearly as option A.

Option C) "when I will wake up" is grammatically awkward and incorrect because it combines a past feeling with a future action. It suggests a far-off time instead of the actual experience.

Option D) "while I wake up" implies an ongoing duration that dilutes the clarity of the moment the weakness is felt.

Thus, A) "when I wake up" is the most precise and natural choice, effectively expressing that the feeling of weakness occurs right at the moment of waking up.