A number of bullets are fired horizontally with different velocities from the top of a tower. They reach the ground

For horizontal projection form a height , considering vertical motion h =   1/2 gt2 .Time taken by the bodies to reach the ground = T =2hg is  same for all the bodies.Horizontal component of velocity remains constant resultant velocity just before hitting the ground =Since 'u' is different for different bullets , resultant velocity will also be different.So option (3) is right.