Find the option that best completes the analogy.

AC : FH :: BD : ?

The correct option is GI.

To find the missing term in the analogy AC : FH :: BD : ?, let us analyze the relationship and pattern between the letters of the first pair (AC and FH):

1. Consider the alphabetical positions of each letter:

• A is the 1^st letter of the alphabet.
• C is the 3^rd letter of the alphabet.
• F is the 6^th letter of the alphabet.
• H is the 8^th letter of the alphabet.

2. Now, examine the shift between corresponding letters from the first group (AC) to the second group (FH):

• First letter: A (1) to F (6) is a shift of +5 positions.
• Second letter: C (3) to H (8) is a shift of +5 positions.

3. Apply the exact same pattern (+5 shift to each letter) to the second pair starting with BD:

• B is the 2^nd letter of the alphabet. Adding 5 to its position gives:
$2+5=7$
The 7^th letter of the alphabet is G.

• D is the 4^th letter of the alphabet. Adding 5 to its position gives:
$4+5=9$
The 9^th letter of the alphabet is I.

Combining these result letters gives GI.