Which of the following pairs replaces ? in series given. B4U, F12P, ?, N108F

The series seems to follow a pattern involving both letters and numbers.

1. Looking at the letters first, they are increasing by 4 in the alphabet: B (2nd letter) to F (6th letter) to ? to N (14th letter). So the first letter of the missing pair should be the 10th letter of the alphabet, which is J.

2. Now looking at the numbers, they seem to be multiplied by 3 each time: 4 to 12 to ? to 108. So the number in the missing pair should be 12*3 = 36.

3. Finally, the last letters U, P, ?, F are decreasing by 6 in the alphabet: U (21st letter) to P (16th letter) to ? to F (6th letter). So the last letter of the missing pair should be the 10th letter of the alphabet, which is J.

So the missing pair in the series is J36J.