Riya a couple of years back.
Celina now, but only for want of better options
Celina is a "photoshoot" girl, not an actress. She knows she can't act, reason patchie already mentioned: a complete blank look all the time (which btw owes from her days at army mess where a friend of mine has seen her getting drunk

I ofcourse never had the pleasure

)
Having said that, with Riya putting on weight, Celina still comes out looking better in her photo ops so will go for Celina
