Definitely #2 is the answer
I believe it's called the urethra
There are more than simply 4 biological compounds in the human body. I suppose to categorise, the question is hinting towards the molecules like Carbohydrates ( Poly and mono saccharides ) Proteins ( Polypeptides Made of amino acids) and Fats. There is also water, but I'm hesitant to class that as a biological compound, as it's not organic.
