Which of the following is not a leap year?

We know that century divisible by 400 is a leap year.

1400 is not divisible by 400.

Hence, 1400 is not a leap year.

Note: Every year divisible by 4 is a leap year, if it is not a century. Every 4th century is a leap year, but no other century is a leap year. 800,1200 and 2000 comes in the category of 4th century (such as 400, 800,1200,1600, 2000 etc). 

Hence, the correct answer is "Option 3".