Final answer:
The government purchase multiplier, given the marginal propensity to consume (MPC) is A. 1/3, is ideally calculated as 1.5. However, this doesn't match any of the options provided, indicating a possible misinterpretation or missing context.
Step-by-step explanation:
If the marginal propensity to consume (MPC) out of current income is equal to 1/3, then to find the government purchase multiplier, we must first identify the marginal propensity to save (MPS). Since MPC + MPS = 1, we can calculate MPS as 1 - 1/3, which is 2/3. The formula for calculating the government purchase multiplier is 1/(1 - MPC). Using the MPC of 1/3, the multiplier would be 1/(1 - 1/3) = 3/2, or simply 1.5.
However, this is not one of the provided options, suggesting there may be a misunderstanding of the question, an issue with provided options, or additional context is needed that affects the multiplier calculation such as taxes or imports. Without additional context or information, the correct interpretation of the multiplier based on the given MPC would lead us to a multiplier of 1.5, not matching any of the answer choices provided (A: 1/3, B: 3, C: 1/1, D: 5).