We need to compare the birth dates starting with the year, followed by month and lastly days.
So we know that 1972 comes the first then 1979 and then 2012
So on arranging all given dates from oldest to latest we will get
1972 - 1979 - 2012
From the given birth dates uncle Tom and Father has the same birth year.
So to check who is older in father and Uncle tom we need to compare the month.
4th month that is april comes earlier to 7th month that is july,
that is 28/04/1972 comes before 10/07/1972
So the correct sequence from old to young would be
Father - Uncle Tom - Aunt Rhea - Sister