Utlisation de c'est avec un adjectif

An unexpected question at C1 level - a problem in the grading ? 

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"C'est" vs "Il/Elle est" to say it is/she is/he is in French  

Standalone adjectives after c'est are always masculine

Wow, merci...mais les leçons sans l'attitude de jugement, si'l vous plaît! Questionner est apprendre

Gus, it was an observation, not a judgement. It is quite reasonable to note there may be some error when the observed is very different to the expected. Bonne continuation.