Der Mann …
A. bist alt.
B. sind Alt.
C. sieht alt aus.
D. seht Alt aus.
http://translation.babylon-software.com/german/to-english/sieht_gut_aus/
Der Mann sieht alt aus.
The correct answer is C. "Der Mann sieht alt aus."
To understand why this is the correct answer, it's important to analyze the sentence construction and use of verb forms in German.
In German, verb forms change based on the subject of the sentence. Here, "Der Mann" is the subject, which is singular. Therefore, we need a verb form that matches the third-person singular pronoun.
Option A, "bist alt," uses the second-person singular form of the verb "sein" (to be). This would be appropriate if we were talking about "du" (you). However, since the subject is "Der Mann," this form is incorrect.
Option B, "sind alt," uses the second-person plural form of the verb "sein" (to be). This would be appropriate if we were talking about "ihr" (you all). Again, since the subject is "Der Mann," this form is incorrect.
Option D, "seht alt aus," uses the second-person plural form of the verb "aussehen" (to look). This would be appropriate if we were talking about "ihr" (you all). However, since the subject is "Der Mann," this form is incorrect.
Option C, "sieht alt aus," uses the third-person singular form of the verb "aussehen" (to look). This is the correct form for the subject "Der Mann," and it correctly translates to "The man looks old" in English.
So, to choose the correct answer in this case, you need to identify the subject of the sentence, understand how verb forms change based on the subject, and select the verb form that matches the subject.