Final answer:
Isaac Newton was likely invited to join France's Academy of Sciences recognizing his contributions to science as an extraordinary scientist from Britain.
Step-by-step explanation:
The statement that is most likely TRUE about Sir Isaac Newton's memberships in Britain's Royal Society and France's Academy of Sciences is c) He was invited to join France's Academy of Sciences as an outstanding scientist from another country. Membership to such prestigious institutions was usually through invitation, extended to individuals recognized for their significant contributions to science. Newton's influential work in physics, mathematics, and natural philosophy, including the publication of his Philosophiae Naturalis Principia Mathematica, would have made him an exemplary candidate for this honor.