The diagram of the human excretory system is given below. Select the option that correctly shows the functions of parts 'a' and 'b'.
1
a - Formation of urine, b - Collection of urine
2
a - Formation of urine, b - Carrying urine for storage
3
a - Formation of urine, b - Throwing urine outside the body
4
a - Collection of urine, b - Formation of urine