`CH_(3)-CH=CH_(2) overset(B_(2)H_(6))underset(H_(2)O_(2), H_(2)O // OH^-) rarr "A"`
`"A"` is

CH_(3)-CH=CH_(2)overset(BD_(3))underset(H_(2))O_(2)//OH^(-))product X,X is:

CH_(3)CH=CH_(2)overset(DB_(3))underset(H_(2)O // OH^())rarr product X X is

CH_3CH_2CH=CH_2 overset(B_2H_6)underset(H_2O_,H_2O_2,OH^-)rarr Z What is Z?

The product "A" in the following reaction is : CH_(3)-CO-CH_(2)COOC_(2)H_(5)underset( H_(2)O)overset( NaOH) ( rarr) A