There are two functional groups present in all amino acids. One is carboxylic and the second is an amine group. The carboxylic acid donate proton so it behaves as acid and amine has lone pair so it can accept the proton and hence behaves as base. Here, in all the given options, only lysine is the one wich has one carboxylic group and two amine groups. Therefore, it is the basic amino acids.
So, the correct option is (A)