According to TAWS-B limitations, what is the rule regarding the use of the 'QFE altimeter setting' (where the altimeter indicates 0 feet on the runway)? (Ref: POH SEC 2-22)

• A) It is recommended.
• B) It is prohibited only in mountainous areas.
• C) Use of TAWS-B is PROHIBITED.
• D) It is mandatory only in IFR flights.