a) A simple reflex agent will be perfectly rational if the environment is fully observable i.e. it has complete information about the present state of the environment at any point of time through its sensors. Also, there shouldn't be any sudden changes in the environment.

b)No, it is not deterministic. If the dirt values of two or more neighboring squares are the same, it randomly choses one to clean and the square cleaned may be different if the robot is run on the same grid again.

c)In an environment in which out of many choices, very few are highly favorable giving good results and all the others lead to bad performance, a randomized agent will perform poorly.

d)In case of noisy sensing, it should take more than one reading for each square and clean a square not just once but for a fixed number of times. This number can be determined by experiment.

e)For the agent to remain rational, the robot should try return to the same square after around every 15 moves and clean it again.