In a certain code, 'ile be pee' means 'roses are blue'; 'sik hee' means 'red flowers' and 'pee mit hee' means 'flowers are vegetables'. How is 'red' written in that code ?

Answer: B. sik

In the second and third statements, the common code word is 'hee' and the common word is 'flowers'. So, 'hee' stands for 'flowers'.
Thus, in the second statement, 'sik' stands for 'red'.