2c/3 is the answer to this question. In order to understand this question, it is important to understand what equivalent capacitance is. This refers to two capacitors that are connected in a parallel manner. Each capacitor is expected to store a certain amount of charge depending on its capacitance.
You will be able to measure the capacitance if you would take note of the total of the different capacitances. You just need to add their value all together. For the capacitator, you need to use the formula that you will use when you are trying to measure resistance. These are details that will be helpful for you.