Explanation:

- APC (Average Propensity to Consume) is the ratio of total consumption to total income (APC = C/Y).

- APS (Average Propensity to Save) is the ratio of total savings to total income (APS = S/Y).

- By definition, all income is either consumed or saved, so APC + APS = 1.

- Let's examine the options:

- ?Option:1 (Not clear)

- ?Option:2 (Not clear)

- 2Option:3 (Not clear)

- 1Option:4 (Possibly 1)

- 0 (Possible answer)

Correct Answer: Option:4 - 1 is correct.

APC + APS always equals 1, because every unit of income is either spent or saved.