Highest setting on: hair tools thermo ceramic hair straightener a or d?

hey on my hair straighteners (hair tools cermaic hair straighteners), it has a little slider with the letters a,b,c and d. and i was wondering does anyone know which is the highest setting a or d? i thought it was a but im not sure now, thanks (: xHighest setting on: hair tools thermo ceramic hair straightener a or d?
Setting A: Max 190C


Setting B: Max 175C


Setting C: Max 160C


Setting D: Max 150C Wattage: 70W

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