When driving in very heavy rain, must the rear fog light be used compulsorily?

A)No, it is only advisable.
B)Yes.Correct
C)No, it is forbidden since there is no fog.
When driving in very heavy rain, heavy snowfall, dense clouds of dust or smoke or thick fog, we must compulsorily use the rear fog light.
FRONT FOG LIGHT:
- Its installation and use is NOT compulsory.
- It will be white or selective yellow.
- It will be used voluntarily in case of fog, heavy rain, snowfall, clouds of smoke or dust or in similar circumstances.
- It may also be used on narrow roads with many curves, that is, those with a roadway 6.5 m wide or less, signposted with «dangerous curves» signs. REAR FOG LIGHT:
- Its installation and use is compulsory.
- It will be red.
- It will be used compulsorily in case of THICK fog, VERY heavy rain, HEAVY snowfall or DENSE clouds of smoke or dust. The front fog light, during the day, may be on alone with the position lights, but may also be used together with the dipped or main beam. At night, it must be used at least with the dipped beam. The rear fog light, during the day, must be used at least together with the front fog light or the dipped beam. At night, at least with the dipped beam.
FRONT FOG LIGHT:
- Its installation and use is NOT compulsory.
- It will be white or selective yellow.
- It will be used voluntarily in case of fog, heavy rain, snowfall, clouds of smoke or dust or in similar circumstances.
- It may also be used on narrow roads with many curves, that is, those with a roadway 6.5 m wide or less, signposted with «dangerous curves» signs. REAR FOG LIGHT:
- Its installation and use is compulsory.
- It will be red.
- It will be used compulsorily in case of THICK fog, VERY heavy rain, HEAVY snowfall or DENSE clouds of smoke or dust. The front fog light, during the day, may be on alone with the position lights, but may also be used together with the dipped or main beam. At night, it must be used at least with the dipped beam. The rear fog light, during the day, must be used at least together with the front fog light or the dipped beam. At night, at least with the dipped beam.