Analysis
To solve this question, we need to observe the given alphabetical series and find the pattern between the related pairs. Let's analyze the given series and the related pairs:

Given series: D L U A E N I O G K S V R M P B H F

Related pairs:
1. LU - EO
2. SV - MH

Pattern Identification
Now, let's try to identify the pattern between the related pairs:

1. LU - EO: If we observe the positions of the letters in the series, L is at position 2 and U is at position 3. Similarly, E is at position 5 and O is at position 6. We can see that the positions of the letters in the related pair are consecutive. Additionally, the letters themselves are consecutive in the series. Therefore, the pattern in this pair is that the positions of the letters in the related pair are consecutive, and the letters themselves are consecutive in the series.

2. SV - MH: Again, if we observe the positions of the letters in the series, S is at position 10 and V is at position 11. Similarly, M is at position 14 and H is at position 15. We can see that the positions of the letters in the related pair are consecutive. Additionally, the letters themselves are consecutive in the series. Therefore, the pattern in this pair is the same as the first pair - the positions of the letters in the related pair are consecutive, and the letters themselves are consecutive in the series.

Applying the Pattern
Now that we have identified the pattern, we can apply it to the letters NI to find the related pair. N is at position 6 and I is at position 7 in the series. Following the pattern, the related pair should have consecutive positions and consecutive letters in the series.

Given options:
a) GS
b) KV
c) GV
d) KR

Analysis of Options
Let's analyze each option to see if it follows the pattern:

a) GS: G is at position 8 and S is at position 11. The positions are not consecutive, so this option does not follow the pattern.
b) KV: K is at position 9 and V is at position 11. The positions are not consecutive, so this option does not follow the pattern.
c) GV: G is at position 8 and V is at position 11. The positions are consecutive, and the letters themselves are consecutive in the series. This option follows the pattern.
d) KR: K is at position 9 and R is at position 13. The positions are not consecutive, so this option does not follow the pattern.

Conclusion
After analyzing all the options, we can conclude that option c) GV is the correct answer. The positions of the letters G and V in the related pair are consecutive, and the letters themselves are consecutive in the series, following the pattern established by the given related pairs LU - EO and SV - MH.