This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Example Input: Passage: 1,500 V DC is used in the Netherlands, Japan, Republic Of Indonesia, Hong Kong (parts), Republic of Ireland, Australia (parts), India (around the Mumbai area alone, has been converted to 25 kV AC like the rest of India), France (also using 25 kV 50 Hz AC), New Zealand (Wellington) and the United States (Chicago area on the Metra Electric district and the South Shore Line interurban line). In Slovakia, there are two narrow-gauge lines in the High Tatras (one a cog railway). In Portugal, it is used in the Cascais Line and in Denmark on the suburban S-train system. Question: How many narrow-gauge lines in Slovakia?
Example Output: two

Example Input: Passage: William Henry Perkin studied and worked at the college under von Hofmann, but resigned his position after discovering the first synthetic dye, mauveine, in 1856. Perkin's discovery was prompted by his work with von Hofmann on the substance aniline, derived from coal tar, and it was this breakthrough which sparked the synthetic dye industry, a boom which some historians have labelled the second chemical revolution. His contribution led to the creation of the Perkin Medal, an award given annually by the Society of Chemical Industry to a scientist residing in the United States for an "innovation in applied chemistry resulting in outstanding commercial development". It is considered the highest honour given in the industrial chemical industry. Question: Which award is named after the discoverer of the dye?
Example Output: Perkin Medal

Example Input: Passage: Dogs have lived and worked with humans in so many roles that they have earned the unique nickname, "man's best friend", a phrase used in other languages as well. They have been bred for herding livestock, hunting (e.g. pointers and hounds), rodent control, guarding, helping fishermen with nets, detection dogs, and pulling loads, in addition to their roles as companions. In 1957, a husky-terrier mix named Laika became the first animal to orbit the Earth. Question: Some dogs help fishermen with what?
Example Output:
nets