Hi. Can anyone explain to me how to solve this question?

Phenazone or also known as antipyrine is an derivative of pyrazolone-5.Antipyrine ia an analgesic,non-steroidal anti-inflammatory and an antipyretic drug.
Its synthesis involves three stages.
First stage which is asked in the above question involves interaction of acetacetic ester (CH3COCH2CO2CH2CH3) with phenylhydrazine(C6H5NHNH2).In this stage there is removal of water molecule(H2O) from O of C=O (from CH3CO) part of acetacetic ester and H2(fromNH2) part of phenylhydarzine which leads to synthesis of molecule Q which is option D of the answer,which is phenylhydarzone acetacetic ester.
C6H5NHN=CCH3CH2CO2CH2CH3