Final answer:
The correct sentence is 'Las playas de México son las más hermosas.' In Spanish, when indicating possession, the preposition 'de' is used. It is also important to note that in Spanish, the definite article 'la' is used before a feminine noun like 'playas' (beaches).
Step-by-step explanation:
The correct sentence is Las playas de México son las más hermosas.
In Spanish, when indicating possession, the preposition 'de' is used. So, 'de México' means 'of Mexico'.
It is also important to note that in Spanish, the definite article 'la' is used before a feminine noun like 'playas' (beaches).
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