Can mps or mpc ever be negative?? give reasons plzz and what about apc and aps??

No, neither MPS nor MPC can ever be negative because MPC is the ratio of change in the consumption expenditure and change in the disposable income. In other words, MPC measures how consumption will vary with the change in income. On the other hand, MPS refers to the ratio of change in savings due to a change in the disposable income.MPC refers to the slope of consumption function which is always positive and MPS refers to the slope of savings function which is always positive because of the positive relationship between the two variables.
Yes, APS can be negative when S is negative or when C > Y. On the other hand, APC can not be negative because ​Average propensity to consume is the ratio of consumption expenditure to a level of income and consumption cannot be negative.