What is the $Tunica \text{ } albuginea$ a covering of?

Which of the following statements is incorrect about Leydig cells?

$A$ pair of bulbourethral glands, also called $...A...$ glands, are present on either side of the $...B...$. They secrete $...C...$ fluid and $...D...$ for lubricating the penis. Here $A, B, C$, and $D$ are:

Given below is a diagrammatic sketch of a portion of the human male reproductive system. Select the correct set of the names of the parts labelled $A, B, C, D$.

Which of the following statements is correct regarding the histology of the seminiferous tubule?

What is the highest concentration found in human seminal plasma?