The normal post-void residual urine in the bladder is a. 250 to 300 ml. b. none of these; non normal residual volume is identified. c. 150 to 200 ml. d. less than 100 ml.

Option D, less than 100 mL.

Explanation:

In general the normal post-void residual urine in the bladder is less than 50 ml. But in case of old patients (of age higher than 65 years) it is acceptable upto the volume of 100 ml. But in younger people it must be less than 50 ml or else it is abnormal.

This leads to the problem of urinary retention which causes frequent urination  or a feeling of incomplete emptying of bladder accompanied sometimes by the urge of overflow incontinence

Thus, if retention is upto 100 ml in old people it is normal .

Option D is correct partially

the genotypes would be 50% bb and 50% bb

the phenotypes would be 50% brown and 50% white. hope this : )