Question:
Who was the head coach of the team Frosinone Calcio in Dec, 2019?

Context:
 Moreno Longo is the head coach of Frosinone Calcio from Jun, 2017 to Dec, 2018. 
 Alessandro Nesta is the head coach of Frosinone Calcio from Jul, 2019 to Dec, 2022. 
 Marco Baroni is the head coach of Frosinone Calcio from Dec, 2018 to Jun, 2019.

Answer:
Alessandro Nesta