Who won men's singles title at the 2019 Australian Open?

Novak Djokovic

The correct answer is Option (2) - Novak Djokovic

Novak Djokovic won the men's singles title at the 2019 Australian Open. He defeated Rafael Nadal in the final to claim his seventh Australian Open title and his 15^th Grand Slam singles title overall. Djokovic's victory solidified his status as one of the greatest tennis players of all time.