Final answer:
The correct substitute for 'A LA DUQUESA' is 'ésta'.
Step-by-step explanation:
The correct substitute for the capitalized words 'A LA DUQUESA' is B. ésta. In Spanish, the article 'a' can be used to indicate possession, and when followed by a feminine noun, it changes to 'a la'. Therefore, the sentence 'El duque ama A LA DUQUESA' translates to 'The duke loves THE DUCHESS'. The word 'ésta' means 'this one' in Spanish, which is the correct substitute in this context.
Learn more about Spanish