Which fog lights are mandatory to use during the day in dense fog?

Which fog lights are mandatory to use during the day in dense fog?
A)Rear fog light.Correct
B)Front fog light.
C)Front and rear fog lights.
FRONT FOG LIGHT:
- Its installation and use is NOT mandatory.
- 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 can 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 mandatory.
- It will be red.
- It will be used, mandatorily, in case of THICK fog, VERY heavy rain, HEAVY snowfall, or DENSE clouds of smoke or dust.
The front fog lights, during the day, may be on alone with the position lights, but may also be used together with the low-beam or high-beam headlights. At night, they will be used at least with the low-beam headlights.
The rear fog lights, during the day, will be used at least together with the front fog lights or low-beam headlights. At night, at least with the low-beam headlights.