Among the following is which one acts as Lewis base?

Amines act as Lewis bases.

Which of the following can act as a Lewis base?

Which of the following can act as a Lewis base?

Which of the following is least likely to act as a Lewis base?

Which of the following compound CANNOT act as a Lewis base ?

Classify the following species into Lewis acis and Lewis bases and show how these act as Lewis acid//base : OH^-