Which of the following statements is true regarding mechanical seals?

Correct Answer: Option B — They are normally lubricated and cooled by the fluid being pumped.

Mechanical seals utilize the pumped fluid itself to provide necessary lubrication and cooling at the interface of the rotating and stationary seal faces. Maintaining a thin fluid film is essential to prevent overheating and premature failure of the seal faces, which are precision-lapped to ensure a leak-free operation.