5. For each of the following assertions, say whether it is true or false. Justify your answers. (6 points: 2 points each) a) Imagine the next Mars rover malfunctions upon arrival on Mars. From this we can deduce that Mars rover is not a rational agent. (Note that a rational agent is not necessarily perfect, it's only expected to maximize goal achievement, given the available information.) b) Every optimal search strategy is necessarily complete. c) Breadth-first search is optimal if the step cost is positive