Sentence:  To repeal the tax (Question I), a 50 per cent majority vote is required. To keep the tax in its 1976 form (Question III), only a <WSD>plurality</WSD> of votes is required. 
Meaning of the word marked with <WSD> tags:  A number of votes for a single candidate or position which is greater than the number of votes gained by any other single candidate or position voted for, but which is less than a majority of valid votes cast.