Règles de la route

All four approaches to a PEI intersection show flashing red. You should treat it as:

Panneau routier de Île-du-Prince-Édouard — A 4-way stop — full stop, yield to right on simultaneous arrival
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Bonne réponse : A. A 4-way stop — full stop, yield to right on simultaneous arrival

Treating flashing red as a full stop is the safe default regardless of whether the signal is damaged or in planned flashing mode.