The bond pays a semiannual coupon of $9\%/2 = 4.5$ per period on `$100` par.

• Yield per semiannual period = $4\%/2 = 2\%$
• Settlement is one month before the next coupon date, so the first coupon is discounted for $1/6$ of a semiannual period.
• There are 5 remaining cash flows: 4 coupons of `4.5` and a final coupon + principal of \`104.5`.

Dirty price:

$$P_{dirty}= \sum \frac{CF_t}{(1.02)^{t}} \approx 113.64$$

where the exponents are $1/6, 7/6, 13/6, 19/6, 25/6$.

Accrued interest:

$$AI = 4.5 \times \frac{5}{6} = 3.75$$

Clean (flat) price:

$$P_{clean}=113.64-3.75=109.89$$

So the nearest answer is A. $109.89.