This sentence tests your knowledge of capitalization and awareness of parallelism. The original sentence is incorrect because choice A destroys the parallelism (i.e. thru advertising instead of simply “advertising”) and uses the informal spelling of through (i.e. “thru”). By ending with “for it” the author is also implying that one may “play for it” and “watch for it,” and although one may play for the World Cup through a grammar stretch, one cannot possibly “watch for it” and do the same thing as one who simply “watches it.” Choice World Cup either through playing, watching or advertising uses the appropriate capitalization (because the World Cup is a major sports event it is a proper noun that must be capitalized) and maintains strict parallelism in the concluding list of ways to be involved.