Answer: D
Explanation: You first have to realize that 26 minutes is the same thing as "under a than half-hour." Once you see this, you know that the question is testing editing out repetition.
The original (answer A) doesn’t work, since it’s repeating the route length already described in the beginning of the sentence. Answer C has the same problem – it’s repeating the route time exactly as already expressed. Answer B takes one type of redundancy and replaces it with another since it’s just a variant of the words “to complete the route” already in the sentence.
So, the only answer that fixes all the redundancies is D.