BRASÍLIA — For millions of voters, Brazil’s presidential election on Sunday is less about who inspires them most than who scares them least.

The front-runners are, for many, wearyingly familiar. President Luiz Inácio Lula da Silva, 80, is running for an unprecedented fourth four-year term; the left-wing leader has already served the most terms, albeit nonconsecutively, of any president in Brazil’s young democracy.