In an unbiased P-N junction 

In an unbiased P-N junction, highly energetic electrons from N-region diffuse into P region by overcoming the potential barrier across the depletion layer. Similarly, highly energetic holes from P-region diffuse into N-region over coming the potential barrier. These electrons and holes constitute the diffusion current which blows from P to N region.

At any temperature, due to thermal agitation, electron-hole pairs are produced and recombine throughout the entire volume of P-N junction. But within the depletion layer, the intense electric field pulls the electrons (minority charge carrier) from P-region to N-region and repel the holes (minority charge carrier) from N to P regions. These electrons and holes constitute drift current. So option (3) is wrong.