A Normal lens for my D90

Hello All,

I am planning to buy a normal lens for my D90.
My question is should I buy

1. the 35mm F2 (with FX image circle) to emulate 50mm on the D90
OR
2. the 35mm F1.8 (with DX image circle)?

Or is there any 50mm DX lens? I could not find any though.
Anything from Sigma, Tokina etc?
Any help will be much appreciated.
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Warm Regards,
Ayan