(10 points) Many operations can be performed faster on sorted data than on unsorted data. For each of the following operations, state whether it could be performed faster if the data values were sorted (do not take the cost of the sorting into account). Please give a brief explanation. Assume an array is used to store data. (a) Find the median value. (b) Calculate the sum of all data in the array. (c) Partition the array according to a given pivot value. (d) Insert a new value to the middle position (which is empty) of the array.