A) 1s on H and 3p on Cl
In HCl, the H atom has only one valance electron. Each share an electron an therefore a single covalent bond is formed between the two. The bond in HCl is therefore a result of an overlap between 1s orbital and ONLY ONE of the lobes of the 3p orbital of Chlorine.
Agitation, or stirring of the solute in the solvent increases the solubility of the solution