For which of the following future years will the calendar of the year 2007 repeat exactly, so that dates and days of the week align in the same pattern for all months?

Introduction / Context:
This question asks which future year has a calendar identical to that of 2007, meaning that every date falls on the same weekday in both years. Calendar repetition is an advanced topic in aptitude tests that depends on the pattern of leap years and the way weekdays shift between years. Correctly identifying repeated calendars shows a strong understanding of these interactions.

Given Data / Assumptions:

• The reference year is 2007.
• Candidate years are 2014, 2019, 2021, and 2018.
• We use standard Gregorian leap year rules.
• A year shares a calendar with 2007 if it is an ordinary year and if 1 January falls on the same weekday.

Concept / Approach:
For two years to have the same calendar, they must both be either leap years or ordinary years, and the weekday of 1 January must be the same in both. Since 2007 is not divisible by 4, it is an ordinary year with 365 days. From one ordinary year to the next, a date typically shifts by one weekday; leap years introduce a shift of two weekdays for dates after February. By tracking these shifts over the years leading to each candidate, we can see which year realigns with 2007.

Step-by-Step Solution:
Step 1: Confirm that 2007 is an ordinary year, since it is not divisible by 4. Step 2: Any matching year must also be an ordinary year, not a leap year. Step 3: Examine candidate years. 2014 and 2018 are ordinary years, while other candidates must be checked for leap year status and weekday alignment. Step 4: By computing weekday shifts year by year from 1 January 2007 and accounting for leap years such as 2008 and 2012, we find that 1 January 2018 falls on the same weekday as 1 January 2007. Step 5: Because both years are ordinary and the starting weekday matches, every date in 2018 aligns with the same weekday as in 2007, giving the same calendar.

Verification / Alternative check:
You can verify this by comparing a printed or digital calendar for 2007 with one for 2018. You will see that 1 January is the same weekday in both years and that all month layouts match exactly. For example, in both years, February has 28 days and the distribution of weekdays across the month is identical. This alignment persists through all twelve months, confirming that 2018 repeats the 2007 calendar pattern.

Why Other Options Are Wrong:
Although 2014 is also an ordinary year, its 1 January weekday does not match that of 2007, so the monthly layouts differ. Years 2019 and 2021 also do not start on the same weekday as 2007 and thus cannot share the exact calendar. In addition, the presence and placement of leap years in the intervening period produce weekday shifts that prevent these years from aligning perfectly with 2007.

Common Pitfalls:
A frequent mistake is to assume that calendars repeat every 7 years automatically. In reality, leap years disrupt this simple pattern. Another pitfall is ignoring whether the candidate year is leap or ordinary before checking alignment. Even if the start day looked close, a leap year would produce a different February and break the calendar match. To avoid such errors, always confirm year type and then consider the cumulative weekday shift across the intervening years.

Final Answer:
Thus, the calendar of the year 2007 repeats in the year 2018 among the options given.