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: Phycobilins are a third group of pigments found in cyanobacteria, and glaucophyte, red algal, and cryptophyte chloroplasts. Phycobilins come in all colors, though phycoerytherin is one of the pigments that makes many red algae red. Phycobilins often organize into relatively large protein complexes about 40 nanometers across called phycobilisomes. Like photosystem I and ATP synthase, phycobilisomes jut into the stroma, preventing thylakoid stacking in red algal chloroplasts. Cryptophyte chloroplasts and some cyanobacteria don't have their phycobilin pigments organized into phycobilisomes, and keep them in their thylakoid space instead. Question: What color is phycoerytherin?
Example Output: red

Example Input: Passage: Industry is diversified, ranging from automotive (Volkswagen Autoeuropa and Peugeot Citroen), aerospace (Embraer and OGMA), electronics and textiles, to food, chemicals, cement and wood pulp. Volkswagen Group's AutoEuropa motor vehicle assembly plant in Palmela is among the largest foreign direct investment projects in Portugal. Modern non-traditional technology-based industries, such as aerospace, biotechnology and information technology, have been developed in several locations across the country. Alverca, Covilhã, Évora, and Ponte de Sor are the main centres of the Portuguese aerospace industry, which is led by Brazil-based company Embraer and the Portuguese company OGMA. Following the turn of the 21st century, many major biotechnology and information technology industries have been founded, and are concentrated in the metropolitan areas of Lisbon, Porto, Braga, Coimbra and Aveiro.[citation needed] Question: What aerospace companies exist in Portugal?
Example Output: Embraer and OGMA

Example Input: Passage: In a time when royals were expected to marry fellow royals, it was unusual that Albert had a great deal of freedom in choosing a prospective wife. An infatuation with the already-married Australian socialite Sheila, Lady Loughborough, came to an end in April 1920 when the King, with the promise of the dukedom of York, persuaded Albert to stop seeing her. That year, he met for the first time since childhood Lady Elizabeth Bowes-Lyon, the youngest daughter of the Earl and Countess of Strathmore and Kinghorne. He became determined to marry her. She rejected his proposal twice, in 1921 and 1922, reportedly because she was reluctant to make the sacrifices necessary to become a member of the royal family. In the words of Lady Elizabeth's mother, Albert would be "made or marred" by his choice of wife. After a protracted courtship, Elizabeth agreed to marry him. Question: How many times did Elizabeth reject Albert's proposal?
Example Output:
twice