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

a) At half of maximum height from  V2−U2=2as,   h=U22g ⇒V2−U2=2gh2⇒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=Ugc) At time ‘2t’ from  V=U+  at    t=Ug,a=−g V=U+2at    ⇒V=U+2−gUg V=U−2U⇒V=−U