Question:
Which position did David Quarrey hold in Jan, 2021?

Context:
 David Quarrey holds the position of ambassador of the United Kingdom to Israel from Jan, 2015 to Jan, 2019. 
 David Quarrey holds the position of National Security Advisor from Sep, 2020 to Mar, 2021. 
 David Quarrey holds the position of Permanent Representative of the United Kingdom to NATO from Apr, 2022 to Dec, 2022.

Answer:
National Security Advisor