Final answer:
More information about the mortgage pool is needed to determine the regular scheduled payment in month 1 of the security.
Step-by-step explanation:
The regular scheduled payment in month 1 of the security can be calculated using the information of the mortgage pool. We need to know the loan amount, interest rate, and term of the mortgage. Without this information, it is not possible to determine the exact monthly payment. Therefore, none of the given options (A, B, C, D) can be confirmed as the correct answer without further details.