Concept:
In letter groups, check alphabetical positions and observe patterns between letters.
Step 1: Convert letters to positions.
(A) BFU:
\[
B(2),\ F(6),\ U(21)
\]
Differences:
\[
+4,\ +15
\]
(B) KOL:
\[
K(11),\ O(15),\ L(12)
\]
Differences:
\[
+4,\ -3
\]
(D) IMN:
\[
I(9),\ M(13),\ N(14)
\]
Differences:
\[
+4,\ +1
\]
Step 2: Check Option (C).
(C) TXD:
\[
T(20),\ X(24),\ D(4)
\]
Differences:
\[
+4,\ -20
\]
Step 3: Identify the pattern.
In most options, the first jump is \(+4\), and the second jump is relatively small (positive or small negative).
But in (C), the second jump is very large negative (\(-20\)), breaking the pattern.
Hence, TXD is the odd one out.