Correct Answer - A
According to equation of continuity `A_(1)v_(1)=A_(2)v_(2)`
`(v_(1))/(v_(2))=(A_(2))/(A_(1))=(piD_(2)^(2)//4)/(piD_(1)^(2)//4)=((D_(2))/(D_(1)))^(2)`
Here, `D_(1)=2.5 cm, D_(2)=3.75 cm`
`therefore (v_(1))/(v_(2))=((3.75)/(2.5))^(2)=((3)/(2))^(2)=(9)/(4)`