A toffee company prepares toffee of two different flavours X and Y. The production of two flavours over a period of 4 years is expressed in the bar graph given below.

What is the difference between the average production of flavour X in 2017 and 2018 and the average production of flavour Y in 2019 and 2020.

A

6000 packs

B

6400 packs

C

7500 packs

D

7000 packs