Final answer:
To calculate the interest, subtract the principal amount from the future value. With the given values, the interest earned over 9 months is $63.00.
Step-by-step explanation:
The question asks us to calculate the interest earned over a period of time given the principal amount (P), the time period (t), and the future value (F) of an investment. Using the values provided, P = $4,200.00, t = 9 months, and F = $4,263.00, the interest can be calculated by subtracting the principal (P) from the future value (F).
Interest = F - P
Interest = $4,263.00 - $4,200.00
Interest = $63.00
Therefore, the interest earned over the 9 months is $63.00, which corresponds with option b.