The sentence ذهب خالد إلى السوق is translated word by word as follows: ذهب means "went" (past tense of the verb ذَهَبَ, to go); خالد is the proper noun "Khalid"; إلى is the preposition "to"; and السوق means "the market" (from the root س-و-ق). Putting these together, the sentence means Khalid went to the market.
The other translations are incorrect because they change either the verb tense or the destination. "Khalid went home" replaces السوق (market) with home (البيت). "Khalid goes to school" changes the tense from past (ذهب) to present (goes) and the destination from market to school (المدرسة). "Khalid went to the mosque" substitutes السوق with the mosque (المسجد). Only the translation that preserves both the past tense and the correct noun السوق is accurate.
Exam tip: In Arabic-to-English translation questions, identify the verb tense first (past: فَعَلَ pattern, present: يَفْعَلُ pattern), then match each noun precisely. السوق specifically means "the market," not any other place.