What a mess. The correct answer would be none of these, since only one of them is a query and it returns NULL. And when this is corrected so that all four are queries, the 4th returns the correct value as well as the third - the claim in the explanation that it returns additional values seems to be incorrect (it doesn't return anything other han the name on my SQL Server 2016 installation, because the query in the question was
select @x.value( '(teams/team[@name="Broncos"]/players/player/name)','varchar(250)' ).
Given the choice between the two correct answers, I picked 4 because it's a marginally more reasonable query - the team part of the search is based on data rather than knowledge of position in some list.
edit: looking at the website now the query (as listed in the results so far) seems to have changed so as to match the explanation.