In the context of leap years in the Gregorian calendar, what is the maximum possible gap in years between two successive leap years?

Introduction / Context:
This conceptual question tests your understanding of the leap year rules in the Gregorian calendar and asks for the maximum possible gap between two successive leap years. Knowing how leap years are determined is essential for many calendar based problems in aptitude exams and for understanding how dates shift over longer periods.

Given Data / Assumptions:
- We are using the Gregorian calendar.
- Leap years normally occur every 4 years.
- Century years require a special rule to decide whether they are leap years.
- We need the maximum possible number of years between two successive leap years.

Concept / Approach:
In the Gregorian calendar, a year is a leap year if:
- It is divisible by 4, and
- If it is a century year (ending with 00), then it must also be divisible by 400 to be a leap year.
This means that most century years like 1700, 1800 and 1900 are not leap years, while 1600 and 2000 are leap years. Because of this exception, there can be an unusually large gap between leap years across a non leap century year.

Step-by-Step Solution:
Step 1: Normally, leap years are 4 years apart (for example, 1992, 1996, 2000), leading to gaps of 4 years.Step 2: Consider a century year such as 1900. It is divisible by 4 but not by 400, so 1900 is not a leap year.Step 3: Look at the leap year just before 1900, which is 1896, and the leap year after 1900, which is 1904.Step 4: The gap from 1896 to 1904 is 8 years.Step 5: This situation shows that when a century year that is divisible by 100 but not by 400 occurs between two leap years, the gap between those leap years becomes 8 years instead of the usual 4.Step 6: No larger gap can occur in the Gregorian system, because between non century leap years the gap remains 4 years.

Verification / Alternative check:
You can test with other centuries: 1796, 1800, 1804 and 2096, 2100, 2104 follow the same pattern. In each case, the non leap century year (1800, 2100) lies between two leap years 8 years apart. This confirms that 8 years is not just an isolated example but a general maximum gap under the Gregorian rules.

Why Other Options Are Wrong:
A gap of 4 years is the standard gap between leap years but not the maximum possible. Gaps of 1 or 2 years cannot occur between leap years, because leap years are at least 4 years apart. A gap of 6 years is also not possible under the combination of the 4 year cycle and the century rules; you either get 4 or, across special centuries, 8 years.

Common Pitfalls:
Many students simply memorise that leap years come every 4 years and ignore the century rule, leading them to choose 4 as the maximum gap. Others think about calendar errors but do not check concrete examples. Always remember the extra rule for century years and test it with actual years to see the 8 year gap clearly.

Final Answer:
The maximum possible gap between two successive leap years is 8 years.