Can someone tell me if I'm on the right track with these intramolecular reactions?

 

For a) I think that an epoxide is formed after NaH takes a Hydrogen from the OH substituent and then the electrons travel making the Cl leave.

 

Then for b I know an epoxide can't form since the OH and the Cl are on the same side. I think the NaH would take the H, so would the product be a resonance structure???

 

For c. I think it's a 5 carbon hetero-cyclic ring with an Oxygen closing the ring + NaH2 and Br-

 

And for d. I think another hetero cyclic ring happens but I don't know what it would look like.I don't know it's substituents or how long it would be since it's not a long chain like how c was.

 

Am I in the right direction?

I think that when sodium hydride accepts a proton, the side products will be Na⁺,Br^- and H₂ gas. I see no reason why an epoxide could not form in d.