The question is asking how much you saved in federal income taxes based on contributions made to an IRA and 401(k) plan, assuming you're in a 25% tax bracket.

To solve it:

1. The total contribution to both the IRA and 401(k) is:

   • $4,500 (IRA) + $2,400 (401k) = $6,900

2. Since these contributions are deducted from your taxable income, the tax savings is calculated as:

   • 25% of $6,900 = $6,900 × 0.25 = $1,725

So, the correct answer is a) $1,725.

Would you like more details on how this is calculated or help with another question? Here's a list of related questions:

1. How does a tax deduction affect your overall tax return?
2. What is the difference between tax credits and tax deductions?
3. How does the tax bracket system work?
4. What other savings options are available to reduce taxable income?
5. What is the maximum annual contribution limit to an IRA and a 401(k)?

Tip: It's always a good idea to maximize contributions to tax-deferred accounts like IRAs and 401(k)s to reduce your taxable income and save on taxes.