!!! which element has three occupied quantum shells with 4 electrons in the outermost shell

Argon. If you look at the periodic table, the noble gases (column on the furthest right of the table - labeled column 18) have fully filled electron shells. This is why noble gases (helium, neon, argon, krypton, xenon, and radon) are not very reactive with other elements - they are happy with their fully filled electron shells. So, the third element down on the noble gas column (Argon) has 3 fully filled electron shells. Periodic table courtesy of Wikipedia

(taken from Quora)

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.