Final answer:
An annuity that can be purchased with one monetary deposit is known as an immediate annuity, and it is pertinent for retirees looking to manage income streams, although it carries inflation risks on a fixed income.
Step-by-step explanation:
The type of annuity that can be purchased with one monetary deposit is called a immediate annuity. This financial product allows an individual to convert a lump sum of money into a stream of payments that typically start within a year of the purchase. In contrast to a deferred annuity, which begins payments at a future date, an immediate annuity starts paying almost right away and is suitable for retirees seeking to manage their retirement income.
Considering the impact of inflation on a fixed income, such as a pension, an immediate annuity could pose a risk if not adjusted for inflation, leading to a decrease in buying power over time.