Why do boiling points increase as the molecules gets longer/bigger?

longer chains of molecules or bigger molecules in general have higher molecular mass so it takes more energy to accelerate the molecules from liquid 2 gas phase. so the bp increases

in chemistry, a solution’s concentration is how much of a dissolvable substance, known as a solute, is mixed with another substance, called the solvent. the standard formula is c = m/v, where c is the concentration, m is the mass of the solute dissolved, and v is the total volume

i believe the answer is a.