The four sentences (labelled 1, 2, 3 and 4) given below, when properly sequenced, would yield a coherent paragraph. Decide on the proper sequencing of the order of the sentences and key in the sequence of the four numbers as your answer.
1. Veena Sahajwalla, a materials scientist at the University of New South Wales, believes there is a new way of solving this problem.
2. Her vision is for automated drones and robots to pick out components, put them into a small furnace and smelt them at specific temperatures to extract the metals one by one before they are sent off to manufacturers for reuse.
3. E-waste contains huge quantities of valuable metals, ceramics and plastics that could be salvaged and recycled, although currently not enough of it is.
4. She plans to build micro factories that can tease apart the tangle of materials in mobile phones, computers and other e-waste.
Sentence 3 establishes the issue: valuable components in e-waste are not efficiently recycled. This provides the discussion's foundation.
Sentence 1 introduces Veena Sahajwalla and her innovative response to the problem in Sentence 3. It logically follows Sentence 3 to link the concepts.
Sentence 4 expands on Sahajwalla's approach, detailing the concept of microfactories for extracting valuable materials from e-waste. This directly supports the assertion in Sentence 1.
Sentence 2 provides further specifics, explaining the integration of drones and robots in the recovery procedure, thus extending the idea presented in Sentence 4.
Furthermore, Sentences 1, 2, and 4 employ pronouns such as "she" and "her", explicitly referring to Sahajwalla introduced in Sentence 1. This reinforces the required order of 3 → 1 → 4 → 2.
Final Sequence: 3 → 1 → 4 → 2
Correct Choice: (D)