The Council shall not have the power to:
(a) Make any contract with or give any official position to any person who is in default to the City;
(b) Sell any property of a value in excess of three hundred and 00/100 dollars ($300.00), as determined by the then market value, unless the said property is offered for sale and an opportunity for free competition be given;
(c) Sell any park, cemetery or any part thereof, or any property bordering on a water front, or vacate any street or public place leading to a water front;
(d) Engage in any business enterprise requiring an investment of money in excess of One Dollar ($1.00) per capita, unless approved by three-fifths (3/5) of the electors voting thereon at any general or special election.