Information concerning a product produced by Ender Company appears here: Required Determine the following: a. Contribution margin per unit. b. Number of units that Ender must sell to break even. c. Sales level in units that Ender must reach to earn a profit of $113,900. d. Determine the margin of safety in units, sales dollars, and as a percentage. Complete this question by entering your answers in the tabs below. a. Contribution margin per unit. b. Number of units that Ender must sell to break even. c. Sales level in units that Ender must reach to earn a profit of $113,900. Complete this question by entering your answers in the tabs below. Determine the margin of safety in units, sales dollars, and as a percentage. (Round "Percentage" answer to 1 decimal place (i.e., 0.234 should be entered as 23.4).)