There are four leading candidates in a race that is still too close to call. Sunday's voting will be followed by a runoff on May 7 between the top two candidates.
Following the controversy, the Singapore Tourism Board (STB) has hit back at the makers of the series with an array of photographs on its Facebook page.
The Ministry of Education says the students in merged schools will get a good spread of enrichment programmes, and the possibility of more subject combinations and CCA options.
The latest attack comes just 10 days before Pope Francis is scheduled to visit Egypt and just a week after the deadly twin church bombings killed 45 people on Palm Sunday in Egypt.