The correct answer is -
The number of phosphoester bond in-
AMP (adenosine monophosphate) = 1
ADP ( adenosine diphosphate) = 1
The number of phosphoanhydride bonds in -
AMP = 0
ADP = 1
Phosphoester bond is formed when the alpha phosphate (that is the first phosphate) present in ADP and AMP links to the 5' carbon of ribose sugar through oxygen.
On the other hand, Phosphoanhydride bond is formed between two phosphate. As ADP has two phosphate, thus it contains one phosphoanhydride bond and the first phosphate is linked to ribose via one phosphoester bond.
AMP has single phosphate, so no phosphoanhydride bond is there, only one phosphoester bond is present in it.