The term alpha ray is a misnomer. In the past alha rays and alpha particles were used interchangeably. B is the correct answer to this queation. I think all of this got started because x-rays really are rays and x-rays are observed with alpha and beta "rays" and "rays" actually do penetrate solid objects just as x-rays do. I think that in technical terms alpha particle, beta particle and x-ray is te proper way to go; however, in the sense that all three actually penetrate solids, the term ray could have some followers.
is not a ray