Answer : The correct option is, (B) Only particle Z
Explanation :
As we know that an atom is the smallest unit of a matter that consist of three subatomic particles which are electrons, protons and neutrons.
The protons and the neutrons are located inside the nucleus or center of the nucleus where the mass of the an atom is concentrated and the electrons are located around or outside the nucleus.
The protons are positively charged, the electrons are negatively charged and the neutrons are neutral that means it has no charge.
As per question, the particle X is positively charged that means it is a proton, the particle Y has no charge that means it is a neutron and the particle Z is negatively charged that means it is an electron.
Hence, the particle most likely present in the space outside of the nucleus of the atom is electrons that means only particle Z.