you/ know/ name/ lecturer/ talk/ natural disasters/ workshop/ two days ago//?

Do you know the name of the lecturer whom talked about natural disasters at the workshop two days ago?

Do you know the name of the lecturer whose talked about natural disasters at the workshop two days ago?

Do you know the name of the lecturer which talked about natural disasters at the workshop two days ago?

Do you know the name of the lecturer who talked about natural disasters at the workshop two days ago?