The conjunction 'although' is incorrect because it means 'even though' and it must be followed by a noun or pronoun. For example, the same sentence can be correctly written as, 'Although she bought a new house, Jane still invested in a new car'. In option (2), the word 'foremost' means 'most prominent in importance' and since this is an adjective, a sentence never begins with this word. In option (3), the word 'until' is wrong because this conjunction means 'up to a certain point of time' which is irrelevant here. In option (1), the preposition 'besides' means 'in addition to / apart from' which fits this context. It means that, in addition to buying a new house, Jane also invested in a car. Hence the correct sentence is, 'Besides buying a new house, Jane also invested in a new car.' Hence the correct answer is option 1.