Explanation:

To calculate autonomous consumption expenditure, use the following formula for equilibrium in the economy:

$$ C = a + cY_d $$

Where:

- \( C \) is total consumption

- \( a \) is autonomous consumption

- \( c \) is the marginal propensity to consume (\( 1 - \text{marginal propensity to save} \))

- \( Y_d \) is disposable income, which equals national income in this case

For the given data:

- National Income (Y) = 1000

- Marginal Propensity to Save = 0.2, so \( c = 1 - 0.2 = 0.8 \)

- Investment Expenditure = 150

Let's make some calculations:

- Aggregate Expenditure (\( AE \)) is \( C + I \)

- At equilibrium, \( AE = Y \), so:

$$ a + 0.8 \times 1000 + 150 = 1000 $$

Rearrange the equation to solve for \( a \):

$$ a = 1000 - 150 - 0.8 \times 1000 $$

$$ a = 1000 - 150 - 800 $$

$$ a = 50 $$

Now, let's review the options:

- Option 1: Z 200

- Option 2: Z 150

- Option 3: Z 950

- Option 4: Z 50

Therefore, the correct option is:

- Option 4: Z 50