Which of the Following Pairs of Siblings Is Most Likely

Which of the following pairs of siblings is most likely to have the closest, warmest relationship?

A) Yarone is 13 years old, and his younger sister Shayla is 8 years old.
B) Tiffany is 5 years old and her younger brother Tajuan is 4 years old.
C) Marquis is 9 years old and is very laid back, and his brother, Lanom, is 7 years old.
D) Jack and his sister Jill are same-aged fraternal twins, and where Jack is very mellow his sister tends to be very emotional.