"A 25-year old single client has just started his own small business and is not covered by a retirement plan. He has $5,000 to invest and currently has a low level of income. He wishes to start saving for retirement. The BEST recommendation is a:"

The BEST recommendation is a ROTH IRA.

Explanation:

The ROTH IRA is far better for this 25-year old with current low income.  His contributions will be tax at a low tax-bracket, thus making his withdrawals at retirement tax-free.  The ROTH IRA is not ideal for high income earners because ordinarily their income will be above the allowed threshold.  The ROTH IRA contrasts sharply with the Traditional IRA where the contributions are made tax-free but the withdrawals are taxed.

if you do not file your taxes you will not have a job, and you credit rate will go down.

answer; capital structure decision;