In a fusion reaction, particles such as atomic nuclei (which are positively charged due to protons) undergo fusion to form a new nucleus. Charged particles are indeed present in these reactions, as they are primarily the nuclei of atoms.
Based on your provided statements, the best choice would likely be:
The nucleus with the greatest positive charge is on the left side of the reaction.
This indicates that in many fusion reactions, the reactants (left side) often have higher total positive charge due to the makeup of their nuclei (particularly in cases like hydrogen fusion where deuterium, tritium, or helium nuclei may be reacting).
If you need a specific context about a particular fusion reaction (like that of helium or hydrogen isotopes), please provide that, and I can refine the explanation accordingly.