In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

What is one example of hydrogen cations?, Context: To avoid the implication of the naked "solvated proton" in solution, acidic aqueous solutions are sometimes considered to contain a less unlikely fictitious species, termed the "hydronium ion" (H3O+). However, even in this case, such solvated hydrogen cations are more realistically conceived as being organized into clusters that form species closer to H9O+4. Other oxonium ions are found when water is in acidic solution with other solvents.
hydronium ion

Who can remove the plague?, Context: A number of non-Greek etymologies have been suggested for the name, The Hittite form Apaliunas (dx-ap-pa-li-u-na-aš) is attested in the Manapa-Tarhunta letter, perhaps related to Hurrian (and certainly the Etruscan) Aplu, a god of plague, in turn likely from Akkadian Aplu Enlil meaning simply "the son of Enlil", a title that was given to the god Nergal, who was linked to Shamash, Babylonian god of the sun. The role of Apollo as god of plague is evident in the invocation of Apollo Smintheus ("mouse Apollo") by Chryses, the Trojan priest of Apollo, with the purpose of sending a plague against the Greeks (the reasoning behind a god of the plague becoming a god of healing is of course apotropaic, meaning that the god responsible for bringing the plague must be appeased in order to remove the plague).
god of plague

What authority had a mess to deal with in the country?, Context: There are many missionary groups operating in the country, including Lutherans, Baptists, Catholics, Grace Brethren, and Jehovah's Witnesses. While these missionaries are predominantly from the United States, France, Italy, and Spain, many are also from Nigeria, the Democratic Republic of the Congo, and other African countries. Large numbers of missionaries left the country when fighting broke out between rebel and government forces in 2002–3, but many of them have now returned to continue their work.
government