Explanation
https://cuckoo.readthedocs.io/en/latest/usage/submit/

FAT is a file system that organizes and stores data on a disk. However, FAT has a limitation of 4 GB for the maximum file size, which means that any file larger than that will be corrupted. To resolve this issue, the engineer can use FAT32, which is an improved version of FAT that supports files up to 32 GB. Alternatively, the engineer can use other file systems that have higher file size limits, such as Ext4 or NTFS. References := Cisco Cybersecurity Operations Fundamentals, Module 5: Security Policies and Procedures, Lesson 5.1: Data Retention, Topic 5.1.1: Data Retention Policies and Procedures

Indirect=circumstantail so there is no posibility to match A or B (only one answer is needed in this question).
For suer it's not a BEST evidence - this FW data inform only of DROPPED traffic. If smth happend inside network, presented evidence could be used to support other evidences or make our narreation stronger but alone it's mean nothing.