Concept:
For an Under-18 tournament, a player must be below 18 years on the date of the tournament.
To determine the exact age in January 2026, we need to identify the exact birth period.
Step 1: Checking Statement (I).
Given:
A is not eligible in December 2026.
This means by December 2026:
\[
\text{Age of A} \geq 18
\]
So A must have completed 18 years on or before December 2026.
But exact birth month is unknown.
Thus, Statement (I) alone is not sufficient.
Step 2: Checking Statement (II).
Given:
A is eligible in September 2026.
This means in September 2026:
\[
\text{Age of A} < 18
\]
So A has not yet completed 18 years by September 2026.
Again, exact birth month is unknown.
Thus, Statement (II) alone is not sufficient.
Step 3: Checking both statements together.
From Statement (I):
By December 2026, A is at least 18.
From Statement (II):
By September 2026, A is still below 18.
Thus, A must complete 18 years between:
\[
\text{October 2026 and December 2026}
\]
So A’s birth must be between:
\[
\text{October 2008 and December 2008}
\]
Hence, in January 2026, A’s age would be between:
\[
17 \text{ years } 1 \text{ month}
\]
and
\[
17 \text{ years } 3 \text{ months}
\]
This gives sufficient information to determine the age range.
Hence, both statements together are sufficient.