An additional unit of Old Product X will bring Cindy an MU of 15 utils, an additional unit of New Product Y will bring Cindy an MU of 30 utils, and an additional unit of New Product Z will bring Cindy an MU of 40 utils. If a unit of Old Product X costs $10, a unit of New Product Y costs $30, and a unit of New Product Z costs $20, which product will Cindy prefer to spend her money on