Explanation:

- Original Sentence: "When have you been waiting for me here?"

This sentence is incorrect because "when" does not appropriately match the question of duration.

- Option 1: How long

"How long have you been waiting for me here?"

This question correctly inquires about the duration of time someone has been waiting.

- Correct Answer!

- Option 2: How far

"How far have you been waiting for me here?"

This option is not correct. "How far" usually refers to distance, not time.

- Option 3: What time

"What time have you been waiting for me here?"

Here, the phrase inquires about a specific point in time, not duration.

- Option 4: How late

"How late have you been waiting for me here?"

This implies urgency or the timing of an event, not the waiting period.