Could you please explain the question every option in detail? Thanks a lot!

Consider a consumer whose marginal utilities are given by MUz (x, y) = VK and MUy (z, y) = = for any x (amount of good x) and y (amount of good y). Suppose that the current market prices are Px = 4 and Py = 2, respectively, and the consumer's income is I = 100. Also, suppose that the consumer currently consumes (x, y) = (10,10). Which of the following statements is true? The consumer could be better off by substituting some of his current consumption of good x with good y. The consumer could be better off by substituting some of his current consumption of good y with good x. ver The consumer could be better off by buying more good x and good y. The marginal rate of substitution of good x is (approximately) 4 at (x. y) = (10. 10)