$7$ Guido is a $67-$year$-$old widower in reasonable health. He has $$75,000$ that he wishes to use to purchase an annuity. Which of the following would provide him with the LOWEST monthly payment?

$$ a$)$ a straight$-$life annuity

b$)$ a life annuity with a $5-$year guarantee

c$)$ a term certain annuity to age $72$

d$)$ a life annuity with a guarantee to age $90$