Final answer:
The symbol that represents radiation with mass and a positive charge is ⁴₂He, which stands for an alpha particle. Hence, option (a) is correct.
Step-by-step explanation:
The symbol that represents a type of radiation that has mass and a positive charge is a. ⁴₂He. This symbol corresponds to an alpha particle, which is a high-energy helium nucleus comprising two protons and two neutrons, and thus has a +2 charge and a mass number of 4.
In contrast, ⁰₀Y and ⁰₋₁ e represent types of gamma radiation and beta particles respectively, which do not have mass and positive charge. The ⁰₀Y symbolizes a gamma ray, which is an uncharged electromagnetic wave with no mass, while the ⁰₋₁ e represents a beta particle, which is a high-energy electron with a negative charge.