निम्नलिखित अक्षर-समूह श्रृंखला में लुप्त पद ज्ञात कीजिए: FLC21, JPG33, ?, RXO57, VBS69

What should come in place of the question mark (?) in the given series based on the English alphabetical order? PPE, NOH, LNK, JMN, ?

Which letter will replace the question mark (?) in the following letter series? U, Q, M, I, ?