`{:(,"Column I",,"Column II",),((A),"Elastic collision",(p),KE " is conserved",),((B),"Inelastic collision",(q),KE "after collision = KE before collision" ,),((C ),"Perfectly inelastic collision",(r ),"KE after collision" != "KE before collision",),(,,(s),"particles stick after collision",),(,,(t),"Linear momentum is conserved",),(,,(u),"Relative velocity of separation after is zero",):}`

Answer

(A) `rarr` q,t; (B) `rarr` r,t; (C ) `rarr` r,s,t,u