Which of the following sentences contains an interlanguage error commonly found in Spanish students' English?

The sentence "Our uncle is doctor" contains an interlanguage error that is commonly observed among Spanish speakers learning English. In Spanish, it is typical to use the definite article ("el") before a profession, leading to the structure "Nuestro tío es el doctor." This reinforces the idea of a specific occupation. However, in English, professions are not preceded by an article unless they are modified by an adjective or further specified. Therefore, the correct English construction should be "Our uncle is a doctor." This type of error highlights the influence of the first language on how learners construct sentences in their second language, resulting in an omission of the indefinite article "a." Such errors are characteristic of the interlanguage stage where learners have not yet fully acquired the grammatical rules of English.