Easy
(Using the same code as the previous question) What is the code for 'Green'?
(Using the same code as the previous question) What is the code for 'Green'?
Comparing 'It is green' (123) and 'Green pet parrot' (728), the digit common to both codes (representing the common word 'Green') is 2.
Re-check your working by substituting the answer back into the original question.