Explanation:

- Option 1: Encourage Consumer Spending

- Credit cards provide consumers with a readily accessible form of credit.

- They make it easier for individuals to purchase goods and services even when they don't have immediate cash.

- This increases consumer spending.

- Option 2: Increase Aggregate Demand In the Economy

- When consumers spend more, businesses see increased sales.

- Increased consumer spending can lead to higher production and employment.

- This boosts aggregate demand in the economy.

- Option 3: Both (a) and (b)

- Credit cards lead to higher consumer spending.

- The rise in spending can increase aggregate demand in the broader economy.

- This combines both effects.

- Option 4: None of these

- This option implies neither statement is correct.

- However, credit cards do influence both consumer spending and aggregate demand.