Explanation: The final sentence states that despite the pursuit of wealth, the traders were “pious, humble, [and] upright,” which matches (D). The attention to tithes would indicate at least some degree of religious orthodoxy, so eliminate (A). The network welcomed cultures from all over the Indian Ocean, including Zoroastrians and Hindus; eliminate (B). There were vast economic opportunities, so (C) is also incorrect. Choice (D) is the answer.