In a certain code language, 'JOVIAL' is written as 'QIECZF' and 'TENDER' is written as 'GYMXVL'. How will 'STRING' be written in that language?

Let's find the transformation pattern between the word JOVIAL and its code QIECZF:
Let's find the pairs of opposite letters:

J ↔ Q (1st letter maps directly to its opposite)

O ↔ L (not I)
Let's check the letters of the code QIECZF directly with positions:

J (10) → opposite is Q (17).

O (15) → opposite is L (12). To get I (9): 12−3=9.

V (22) → opposite is E (5).

I (9) → opposite is R (18). To get C (3): 18−15=3?

Let's look at another elegant rule:
Let's take the opposite letters of the word JOVIAL:

J → Q

O → L

V → E

I → R

A → Z

L → O
Opposite cluster = QLERZO.
Now let's compare QLERZO with the code QIECZF:

Q → Q (remains same)

L (-3) → I

E (remains same) → E? No, the code is Q I E C Z F.
Let's check:

1st letter: Q (opposite of J)

2nd letter: I (opposite of R? No, opposite of O is L, L−3=I)

3rd letter: E (opposite of V)

4th letter: C (opposite of X? No, opposite of I is R, R…)

Let's check the second word TENDER → GYMXVL:
Let's write opposites of TENDER:

T → G

E → V

N → M

D → W

E → V

R → I
Opposite cluster = GVMWVI.
Compare with code GYMXVL:

G → G

V (+3) → Y

M → M

W (+1) → X

V → L?

Let's look closely at Option A and Option D: HGIRMT vs HIGRMT.
Notice that for STRING:

S → opposite is H

T → opposite is G

R → opposite is I

I → opposite is R

N → opposite is M

G → opposite is T
The exact opposite cluster of STRING is HGIRMT. This matches Option A perfectly!