Between a young, muscular 25-year-old male and an older 75-year-old female with higher body fat percentage, which person is expected to have the higher percent body water and why?

The older female because age-related loss of kidney concentrating ability increases extracellular water relative to intracellular compartments, which raises total body water percentage despite more fat

The young muscular male because muscle contains more water than adipose tissue so higher lean mass increases total body water percentage

They will have essentially identical percentages because sex and age do not meaningfully affect total body water when calorie intake is controlled

The older female because hormonal changes after menopause cause increased water retention within adipose tissue leading to a higher overall water fraction when averaged across total body mass