Which shows the best use of parentheses?
When did Magic Johnson first lead his professional team to a world championship: a 1980, b 1981, or c 1982?
When did Magic Johnson first lead his professional team to a world championship: (a 1980, b 1981, or c 1982?)
When did (Magic Johnson) first lead his professional team to a world championship: a 1980, b 1981, or c 1982?
When did Magic Johnson first lead his professional team to a world championship: (a) 1980, (b) 1981, or (c) 1982?
When did Magic Johnson (first lead his professional team) to a world championship: a 1980, b 1981, or c 1982?