I think the correct answer would be that there are a relatively small number of moles of HCl present. Dilute would mean that there are very few solute particles dissolved as compared to the solvent particles in the solution. Hope this helps.
I uploaded the answer to a file hosting. Here's link:
tinyurl.com/wpazsebu
I think the answer would be Switch 1 open; switches 2, 3, and 4 closed. It is letter D. This will happen when there is a low resistance and a high circuit so from the choices above, when two bulbs are open and one bulb is close, so there is a low resistance and high voltage.