A body thrown is  vertically up with a velocity ‘U ’from ground. It reaches the maximum height ‘H’ in ‘t’  seconds. Then  the correct statement among the following is

a)  we know for vertical projection ,   h=U22g=maximum height reached by a body V2−U2=2as;   here v is final velocity;u is initial velocity; a is acceleration ; s is displacement;  At half of maximum height , put height=h2⇒V2−U2=2gh2substitute h=U22g⇒V2−U2=−gU22g⇒V2−U2=−U22⇒V2=−U22+U2⇒V=U2b) At time ‘t’ the body is in maximum height its velocity is zero. ‘t’ is time of ascent t=Ug c) we know,V=U+  at  time of ascent is    t=Ug, for vertically projected body →a=−g substitute time =2t in      v=u+at V=U+2at  substitute time of ascent=t=Ug    ⇒V=U+2−gUg V=U−2U ⇒V=−U  =velocity of the body after time =2t