Complex sentence: Exactly which island in the Bahamas this corresponds to is an unresolved topic; prime candidates are Samana Cay, Plana Cays, or San Salvador Island (so named in 1925 in the belief that it was Columbus's San Salvador).
Split into simpler sentences: Exactly which island in the Bahamas this corresponds to is unresolved. Prime candidates are Samana Cay, Plana Cays, or San Salvador Island (so named in 1925 in the belief that it was Columbus's San Salvador).