Solve the following question and mark the best possible option.
Mr. and Mrs. Shah have two children Arti and Saurabh. Saurabh married Ritu, daughter of Mr. Mehra. Shakti, son of Mrs. Mehramarries Reena. Subash and Rishabh are born to Shakti and Reena. Mukti and Shruti are the daughters of Saurabh and Ritu. How is Shakti related to Shruti?