(a) A district may not impose a tax or increase the rate of an existing tax unless a proposition proposing the imposition or rate increase is approved by a majority of the votes received at an election held for that purpose.
(b) Each new tax or rate increase must be expressed in a separate proposition consisting of a brief statement of the nature of the proposed tax.
(c) The notice of the election must contain a statement of the base or rate of the proposed tax.