A. A weight gain of 16.4 to 20.5 kg (36 to 45 lb) is excessive for a client with a pre-pregnancy BMI of 21, which falls within the normal range. Such weight gain is more appropriate for an underweight client. B. A weight gain of 5 to 7.7 kg (11 to 17 lb) is inadequate for a client with a normal pre-pregnancy BMI. This range is suitable for an overweight or obese client. C. A pre-pregnancy BMI of 21 falls within the normal range (18.5–24.9), and the recommended weight gain for clients in this category is 11.4 to 15.9 kg (25 to 35 lb). This range supports healthy fetal growth and reduces the risk of complications. D. A weight gain of 8.2 to 10.9 kg (18 to 24 lb) is slightly below the recommended range for a client with a normal BMI and may not adequately support fetal development. This range is more appropriate for overweight individuals.