Which statement about left recursion in context-free grammars is accurate?

1. ALeft recursion can be direct or indirect and may lead to infinite recursion in top-down parsers.
2. BLeft recursion is required for building LL(1) parsers without any modification.
3. CLeft recursion has no impact on recursive-descent parsing.
4. DLeft recursion occurs when a non-terminal appears at the end of its own production.