Question

When did people begin to notice that coastlines of continents fit together like puzzle pieces?

when satellites began taking pictures of Earth from space
when Alfred Wegener proposed the idea of continental drift
when early explorers traveled from Europe and Asia to the Americas
when geologists first started examining the fossil record of South America

Answer 1

when early explorers traveled from Europe and Asia to the Americas

Maps made after those voyages showed the matching shapes of coastlines (notably South America and Africa); mapmakers like Abraham Ortelius in the 16th century even suggested the continents had once been joined.