In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Question: Which of the regiments that Ellwood served in was the largest? Passage:Ellwood graduated from Duntroon in 1990 and was commissioned into the Royal Australian Infantry Corps. His early career included postings as a platoon commander in the 2nd/4th Battalion, Royal Australian Regiment and as an instructor in field training and tactics at Duntroon, before he was seconded to the British Army from 1998 for a two-year exchange with the Irish Guards, then stationed in Germany. During the secondment he deployed as part of the NATO intervention in the Kosovo War in 1999, serving as second-in-command of an armoured infantry company in the King's Royal Hussars Battle Group. For his service in Kosovo, Ellwood was awarded a Commander British Forces Commendation. He returned to Australia as a company commander and operations officer in the 5th/7th Battalion, Royal Australian Regiment (5/7RAR). Ellwood commanded B Company on operations in East Timor from October 1999 to April 2000, when 5/7RAR deployed with the International Force East Timor.
 Links: a. 2nd/4th Battalion, Royal Australian Regiment b. Kosovo War c. 2nd/4th Battalion, Royal Australian Regiment d. King's Royal Hussars
a

Question: How often are new issues of the Canadian Journal of Neurological Sciences published? Passage:Multi-dose versions of the vaccine contain the preservative thiomersal (also known as thimerosal), a mercury compound that prevents contamination when the vial is used repeatedly. Single-dose versions and the live vaccine do not contain this preservative. In the U.S., one dose from a multi-dose vial contains approximately 25 micrograms of mercury, a bit less than a typical tuna fish sandwich. In Canada, different variants contain five and 50 micrograms of thimerosal per dose. The use of thiomersal has been controversial, with claims that it can cause autism and other developmental disorders. The U.S. Institute of Medicine examined these claims and concluded in 2004 that the evidence did not support any link between vaccines and autism. Other reviews came to similar conclusions, with a 2006 review in the Canadian Journal of Neurological Sciences stating that there is no convincing evidence to support the claim that thimerosal has a causal role in autism, and a 2009 review in the journal Clinical Infectious Diseases stating that claims that mercury can cause autism are "biologically implausible". The U.K. National Health Service stated in 2003 that "There is no evidence of long-term adverse effects due to the exposure levels of thiomersal in vaccines." The World Health Organization concluded that there is "no evidence of toxicity in infants, children or adults exposed to thiomersal in vaccines". Indeed, in 2008 a review noted that even though thiomersal was removed from all US childhood vaccines in 2001, this has not changed the number of autism diagnoses, which are still increasing.
 Links: a. Thiomersal and vaccines b. Autism c. Canadian Journal of Neurological Sciences d. National Academy of Medicine
c

Question: How many people died in the battle that the 1st battalion saw action at in August 1807? Passage:A second battalion was raised in 1804 to increase the strength of the regiment. The 1st battalion embarked for Copenhagen in July 1807 and saw action at the Battle of Copenhagen in August 1807 during the Gunboat War before returning home in November 1807. It then embarked for Portugal in May 1808 for service under General Sir Arthur Wellesley in the Peninsular War and saw action at the Battle of Roliça in August 1808 and the Battle of Vimeiro later that month. In January 1809 the battalion took part in the Battle of Corunna, carrying out successive bayonet charges to keep the French at bay to which General Sir John Moore shouted "Well done, 50th! Well done, my Majors!". The battalion was subsequently evacuated from the Peninsula. Both battalions then embarked from the Downs in July 1809 and saw action in the disastrous Walcheren Campaign. It was the last regiment to leave Holland in December 1809.
 Links: a. Arthur Wellesley, 1st Duke of Wellington b. Battle of Copenhagen (1807) c. The Downs (ship anchorage) d. Copenhagen

b