Correct option is C
Given - PETAL is coded as 11-22-7-26-15.
Logic - all the number o codes are place values of respective letters given in the word.
place values of letters.

Ask -How will UNDER -
U - opposite letter F - place values = 6
similarly,
N -13
D -23, E- 22, R - 9
UNDER will coded as - 6-13-23-22-9
option c is correct answer.