Answer : Option 'b' is correct.
Explanation :
Since we know that the length of apparent solar day= 24 hours approximately
And the length of normal days = 23 hours 56 minutes 4.1 seconds
So, the approximate length of an apparent solar day from June 21, 2010 to June 22, 2010 will be 24 hours 0 minutes 4.1 seconds .
As we increase the length of normal days by 4 minutes .
So, Option 'b' is correct.