Which of the following expressions would you use in formal, informal and ^Nv^ neutral situations?

Neutral
Could you tell me please.?
Excuse me. do you know.?
D'you happen to know
I'd like to know..., please
Can you tell me., please

lnformal
(Happen to) know.?
(Got) any idca.?

Formal
I wonder if you could tell me.
I should be interested to know.