Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Ex Input:
Context: 51827 Laurelclark (2001 OH38) is an asteroid named for astronaut Laurel Clark, who was killed in the STS-107 (Columbia) space shuttle reentry disaster on February 1, 2003. 
 Question: Whom is 51827 Laurelclark named after?

Ex Output:
laurel clark


Ex Input:
Context: In the county, the population was spread out with 23.20% under the age of 18, 7.70% from 18 to 24, 27.00% from 25 to 44, 28.00% from 45 to 64, and 14.10% who were 65 years of age or older. The median age was 40 years. For every 100 females, there were 97.00 males. For every 100 females age 18 and over, there were 96.40 males. 
 Question: Which age group is smaller: 25 to 44 or 45 to 64?

Ex Output:
25 to 44


Ex Input:
Context: Osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand (RANKL) are dominant regulators of bone resorption. Many hormones, cytokines and growth factors mediate bone resorption by altering the ratio of RANKL to OPG. RANKL and OPG expression is also altered in numerous bone diseases, and these changes can reflect disease etiology or compensatory responses to disease. RANKL stimulates osteoclast formation, function and survival, and each of these effects is inhibited by OPG. OPG suppresses bone resorption and increases the density, area and strength of both cancellous and cortical bone. Denosumab (AMG 162), a fully human monoclonal antibody to RANKL, shares the pharmacologic attributes of OPG but has a significantly longer half-life that allows less frequent administration. 
 Question: To the ligand of which receptors does Denosumab (Prolia) bind?

Ex Output:

rankl