TASK DEFINITION: This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
PROBLEM: Passage: Because of their long life, fast switching times, and their ability to be seen in broad daylight due to their high output and focus, LEDs have been used in brake lights for cars' high-mounted brake lights, trucks, and buses, and in turn signals for some time, but many vehicles now use LEDs for their rear light clusters. The use in brakes improves safety, due to a great reduction in the time needed to light fully, or faster rise time, up to 0.5 second faster[citation needed] than an incandescent bulb. This gives drivers behind more time to react. In a dual intensity circuit (rear markers and brakes) if the LEDs are not pulsed at a fast enough frequency, they can create a phantom array, where ghost images of the LED will appear if the eyes quickly scan across the array. White LED headlamps are starting to be used. Using LEDs has styling advantages because LEDs can form much thinner lights than incandescent lamps with parabolic reflectors.

SOLUTION: Why are non-LED lights sought after for various applications?

PROBLEM: Passage: Samkhya school espouses dualism between consciousness and matter. It regards the universe as consisting of two realities; Puruṣa (consciousness) and prakriti (matter). Jiva (a living being) is that state in which puruṣa is bonded to prakriti in some form. This fusion, state the Samkhya scholars, led to the emergence of buddhi (awareness, intellect) and ahankara (individualized ego consciousness, “I-maker”). The universe is described by this school as one created by Purusa-Prakriti entities infused with various permutations and combinations of variously enumerated elements, senses, feelings, activity and mind.

SOLUTION: What school rejects dualism?

PROBLEM: Passage: Dell was the first company to publicly state a timeline for the elimination of toxic polyvinyl chloride (PVC) and brominated flame retardants (BFRs), which it planned to phase out by the end of 2009. It revised this commitment and now aims to remove these toxics by the end of 2011 but only in its computing products. In March 2010, Greenpeace activists protested at Dell offices in Bangalore, Amsterdam and Copenhagen calling for Dell’s founder and CEO Michael Dell to ‘drop the toxics’ and claiming that Dell’s aspiration to be ‘the greenest technology company on the planet’ was ‘hypocritical’. Dell has launched its first products completely free of PVC and BFRs with the G-Series monitors (G2210 and G2410) in 2009.

SOLUTION:
What toxic chemical didn't Dell set to eliminate from its products?