Please Correct Me

Hi,

Below are few sentences, please tell me which one is correct :-

1a. Kindly explain which kind of project are you working?
1b. Kindly explain which kind of project are you working on?
1c. Kindly explain on which project are you working?

2a. Is it happened daily?
2b. Does it happen daily?

What do you think, MyEfforts?

Beeesneees, I’m afraid I didn’t understand your meaning, I mean I did get whether you’re kidding with me or asking seriously?

As per my knowledge :-

1b is correct
2a is correct

I was asking you seriously. If you put in the thought yourself you will learn far more than if you are simply told the answer, so I was asking you to think about it.

The word order in 1b and 1c is wrong. It should be
Kindly explain which kind of project you are working on.
Kindly explain on which project you are working.
1a is completely incorrect.

2a cannot be correct - ‘Is it’ is present tense / ‘happened’ is past tense.
2b is correct.