The correct answer is A. Suresh asked how long it will take to travel from Germany to South Africa.
The sentence “How long will it take to travel from Germany to South Africa?” is a question asking for the duration of a trip. The word “will” indicates that the speaker is asking about the future, and the word “take” indicates that the speaker is asking about the time it will take to complete an action.
Option B is incorrect because the word “would” indicates that the speaker is asking about a hypothetical situation. Option C is incorrect because the word “would” indicates that the speaker is asking about a hypothetical situation, and the word “take” indicates that the speaker is asking about the time it will take to complete an action. Option D is incorrect because the word “must” indicates that the speaker is asking about a requirement, and the sentence does not indicate that there is a requirement for the duration of the trip.