Which answer is correct?

Bind `this` in the constructor: `this.handleClick = this.handleClick.bind(this)`. This ensures `this` always refers to the instance.

— bind_advocate

Use an arrow function for the method: `handleClick = () => { ... }`. Arrow functions capture `this` from their enclosing scope (the class instance).

— arrow_fan

Wrap the call in an arrow: `onClick={() => this.handleClick()}`. The arrow captures `this` at the call site.

— inline_wrapper

Use `"use strict"` at the top of the file. Strict mode fixes `this` binding.

— strict_believer