Bottleneck process (Kaplan 240.2)

Hello dear tutor, I have a long question. Even though I try every time, I cannot understand the process. Could you please explain it to me in a simple way? I would really appreciate it. Sweet Treats Bakery makes three types of cake: brownies, muffins and cupcakes. The costs, revenues and demand for each of the three cakes are as follows: .............................................Brownies ..............Muffins .............Cupcakes Batch size (units) .................... 40........................30.......................20 Selling price ($ per unit) ....... 1,5 ...................... 1,4 .......................2 Material cost ($ per unit) ..... 0,25 .................... 0,15 ................... 0,25 Labour cost ($ per unit) ....... 0,40 .................... 0,45 ................... 0,50 Overheads ($ per unit) ........ 0,15 ..................... 0,20 ................... 0,30 Minimum daily demand (units)..30....................20........................10 Maximum daily demand (units)..140..................90.......................100 The minimum daily demand is required for a long-term contract with a local café and must be met. The cakes are made in batches using three sequential processes: weighing, mixing and baking. The products must be produced in their batch sizes but are sold as individual units. Each batch of cakes requires the following amount of time for each process: .............................................Brownies ..........Muffins .............Cupcakes Weighing (minutes) .............. 15.....................15.......................20 Mixing (minutes) .................... 20.................... 16.......................12 Baking (minutes) .................. 120.................... 110................... 120 The baking stage of the process is done in three ovens which can each be used for eight hours a day, a total of 1,440 available minutes. Ovens have a capacity of one batch per bake, regardless of product type. Sweet Treats Bakery uses throughput accounting and considers all costs, other than material, to be ‘factory costs’ which do not vary with production. QUESTION: On Wednesday, the mixing process is identified as the bottleneck process. On this day, only 120 minutes in the mixing process are available. Assuming that Sweet Treats Bakery wants to maximise profit, what is the optimal production plan for Wednesday? A) 80 brownies, 30 muffins and 100 cupcakes B) 0 brownies, 90 muffins and 100 cupcakes C) 120 brownies, 0 muffins and 100 cupcakes D) 40 brownies, 60 muffins and 100 cupcakes