Scala quiz. What will be the result of combineAll for the foll

What will be the result of combineAll for the following Monoid?

import cats.implicits._
import cats.kernel.Monoid

Monoid[String].combineAll(List())

List()
""
None
Nil

Explanation

Function combineAll can take List as a parameter. In current example, it is an empty list. Since Monoid is of type String, the combine is done for empty list of Strings that returns a zero value, which is an empty String.

Source: Scala Exercises: cats monoid