The correct answer is C) Estimated time of finishing cargo. The pre-transfer conference is required to discuss various safety and operational details before commencing cargo transfer operations. However, the estimated time of finishing cargo is not a mandatory topic that must be covered during this conference. The required topics typically focus on emergency procedures, product identification, and the specifics of the transferring and receiving systems involved. The other options, A) Emergency shutdown procedures, B) Identity of the product to be transferred, and D) Details of transferring and receiving systems, are all relevant and required topics that must be discussed during the pre-transfer conference.