Final answer:
The correct form is 'has' for the infinitive 'to have' in the sentence, completing the present perfect tense.
Explanation:
The correct present tense form of the infinitive to have for the sentence is:
The cracked windshield, in addition to the torn upholstery and rusted body, has made Ruth's old car difficult to sell.
This sentence demonstrates the use of the present perfect tense, where 'has' is the correct auxiliary verb accompanying the past participle 'made' to show an action that was recently completed.
Learn more about Present perfect tense and auxiliary verbs here:
https://brainly.com/question/11036517
