Transform the sentence 'Benim bir arabam var.' (I have a car.) into the genitive case to indicate possession by 'Ali'. What is the resulting sentence, and which case ending is used?

To transform 'Benim bir arabam var.' (I have a car.) to indicate possession by 'Ali', we need to change the possessor from 'I' to 'Ali'. In Turkish, possession is often indicated using a genitive case for the possessor and a possessive suffix for the possessed item. The original sentence uses 'benim' (my), which is the genitive form of 'ben' (I), and 'arabam' (my car), where '-m' is the first-person singular possessive suffix. To show that Ali possesses the car, we need to make 'Ali' the possessor. The genitive case in Turkish for proper nouns like 'Ali' is formed by adding the suffix '-nin' if the noun ends in a vowel, or '-ın', '-en', '-un', '-ün' depending on vowel harmony if it ends in a consonant. Since 'Ali' ends in a vowel 'i', we add '-nin', making it 'Ali'nin'. The possessed noun, 'araba' (car), needs a third-person singular possessive suffix, which is '-sı' after a vowel. So, 'araba' becomes 'arabası' (his/her/its car). The verb 'var' (there is/exists) remains the same. Therefore, the resulting sentence is 'Ali'nin arabası var.' (Ali has a car.). The case ending used for 'Ali' to show possession is '-nin', which is the genitive case ending for proper nouns ending in a vowel.