Answer:
a. 10 years
Step-by-step explanation:
Investing for retirement is a long-term project. The earlier a person starts to invest, the better for them as they will enjoy the benefits of compounding.
Ideally, saving for retirement should start the moment one gets employed. This gives them ample time to save and accumulate money for use in retirement. There is no upper limit as to how many years one should save for retirement. However, one needs to save for at least ten years to have sufficient funds for retirement.