Modules X and Y operate on the same input and output, then the cohesion is

Explanation

Communicational (communication) cohesion is defined precisely as the case where the elements of a module operate on the same input data or contribute to the same output data, which is what the question states. In sequential cohesion the output of one element becomes the input of the next, forming a chain rather than a shared data set. In procedural cohesion the elements are grouped only because they must execute in a particular control order. In logical cohesion elements belong to the same general class of functions and one is selected by a flag. Hence option 4.