Consider the following normal$-$form game.

Player $1\backslash$ Player $2$CDA$1,11,1$B$1,10,1$

None of the answers is correct.

The game has exactly two Nash equilibria in pure strategies: $($A$,$C$)$ and $($A$,$D$).$

This game has a unique Nash equilibrium in mixed strategies.

IESDS permits us to eliminate B$.$

The game has infinitely many Nash equilibria, in each of which one of the two players plays a mixed strategy, while the other plays a pure strategy.