regarding
3.1. At the conclusion of the election, each option is assigned all ballots which express it as first preference. The option with the fewest ballots assigned to it is eliminated. Each ballot cast for the eliminated option is reassigned to the next expressed preference on the ballot.
and
3.4. If any ballot assigned to an eliminated option does not express a next preference, the ballot is treated in the same way as an abstention.
I would suggest that the the option to vote to rank only one, or otherwise less than the total number of options be specifically noted in voting instructions. This will allow those who wish to make a clear focused selection to do so, rather than being confused with the appearance of having to select an option that they do not support in any manner.