Select the option that is related to the fifth letter cluster in the same way as the second letter cluster is related to the first letter cluster and the fourth letter cluster is related to the third letter cluster.
$$\text{COLOUR : CUOLOR :: TRIBAL : TABIRL :: FINGER : ?}$$

Let's track how the letters switch positions: ${\text{C}}_1{\text{O}}_2{\text{L}}_3{\text{O}}_4{\text{U}}_5{\text{R}}_6\to {\text{C}}_1{\text{U}}_5{\text{O}}_2{\text{L}}_3{\text{O}}_4{\text{R}}_6$ Wait, let's look at a simpler adjacent swap or index movement:Positions: $1,2,3,4,5,6$ In COLOUR $\to$ CUOLOR:Keep 1st and 6th positions fixed ($\text{C}$ and $\text{R}$).The middle part $\text{O L O U}$ is shifted/reordered to $\text{U O L O}$. This is a right-cyclic rotation of the middle 4 letters by 1 step.Let's verify with TRIBAL $\to$ TABIRL:Keep 1st and 6th positions fixed ($\text{T}$ and $\text{L}$).Middle letters $\text{R I B A}$ are right-rotated by 1 step $\to$ $\text{A R I B}$.Result: TABIRL. Logic holds perfectly!Now let's apply this to FINGER:Keep 1st and 6th positions fixed ($\text{F}$ and $\text{R}$).Middle letters $\text{I N G E}$ are right-rotated by 1 step $\to$ $\text{E I N G}$.Resulting cluster: FEINGRLet's double check option alternatives because FEINGR is not in choices. Let's see another swapping mechanism:Let's look at vowel/consonant segregation or alphabetical sorting of middle letters?In COLOUR: $\text{O, L, O, U}$ sorted? No.Let's see: $\text{C}(\text{O}\leftrightarrow \text{U}\dots )$ What if it swaps specific pairs?In COLOUR: $\text{C}\text{O}\text{L}\text{O}\text{U}\text{R}$ Let's look at choice A: FEGINRCompared to FINGER:$\text{F}\to \text{F}$$\text{I}\to \text{E}$$\text{N}\to \text{G}$$\text{G}\to \text{I}$$\text{E}\to \text{N}$$\text{R}\to \text{R}$ Let's look at the actual positional mapping from COLOUR to CUOLOR:${\text{C}}_1\to {\text{C}}_1$${\text{O}}_2\to {\text{O}}_3$${\text{L}}_3\to {\text{L}}_4$${\text{O}}_4\to {\text{O}}_5$${\text{U}}_5\to {\text{U}}_2$${\text{R}}_6\to {\text{R}}_6$ Indices become: $1,5,2,3,4,6$.Let's test this index order $1,5,2,3,4,6$ on TRIBAL:$1\to \text{T}$$5\to \text{A}$$2\to \text{R}$$3\to \text{I}$$4\to \text{B}$$6\to \text{L}$ Result: TARIBL, but the question text says TABIRL.Ah, let's check TABIRL closely:${\text{T}}_1\to {\text{T}}_1$${\text{R}}_2\to {\text{R}}_4$${\text{I}}_3\to {\text{I}}_3$? No, $\text{B}$ is at 5. Let's check:${\text{T}}_1{\text{A}}_5{\text{B}}_4{\text{I}}_3{\text{R}}_2{\text{L}}_6$.The middle 4 letters are completely reversed!Let's check if reversing the middle 4 works for COLOUR:Middle 4 letters of COLOUR: $\text{O L O U}\to \text{reversed}\to \text{U O L O}$.Result: CUOLOR. Yes! It works perfectly!Now let's apply the "reverse middle 4 letters" rule to FINGER:Keep $\text{F}$ and $\text{R}$ fixed.Middle 4 letters: $\text{I N G E}\to \text{reversed}\to \text{E G N I}$.Final string: FEGNIR.This matches Option C exactly.