How many outer atoms and lone pairs are present in a molecule with a see-saw shape?

There are 4 outer atoms and lone pairs that are present in a molecule with a see-saw shape. It was called "seesaw" comes from the observation that it looks like a playground seesaw. It is very common that four bonds to a central atom result in tetrahedral or, less commonly, square planar geometry. 

The answer is a. i hope this