If 'PURSER' is coded as 'UPSRRE', then how will 'PERIODIC' be coded?

EPRIDOIC PEIRDOCI EPIRDOCI EPIRODCI

EPIRDOCI

According to the question, the pattern which is observed is as follows: 1st and 2nd letters are interchanged, 3rd and 4th letters are interchanged, and 5th and 6th letters are interchanged. So, following the same pattern "PERIODIC" will be coded as EPIRDOCI