Answer: The correct answer is c. $943.87.
Step-by-step explanation: To solve this problem, we need to first determine the length of time between October 1 and July 1 of the following year. This is a period of 9 months, or 3 quarters. We can then use this information to calculate the amount of interest earned over this time period.
The principal in Yujin Pon's account is $900, and the interest rate is 6.5% compounded quarterly. This means that for each quarter, the account will earn 6.5/4 = 1.625% in interest. Over the 3 quarters between October 1 and July 1 of the following year, the account will earn a total of 1.625% * 3 = 4.875% in interest.
To calculate the amount of interest earned, we can multiply the principal by the interest rate:
Interest = Principal * Interest Rate
= $900 * 0.04875
= $43.87
The total amount in the account on July 1 will be the original principal plus the amount of interest earned over the 3 quarters:
Total = Principal + Interest
= $900 + $43.87
= $943.87
Therefore, the correct answer is c. $943.87.