30. According to Coast Guard Regulations (46 CFR), no vessel can come alongside or remain alongside a tank vessel while it is loading A, B, or C grade cargo without having the permission of the __________.

According to Coast Guard Regulations, a vessel requires permission from the officer in charge of the vessel loading Grade A, B, or C cargo before coming alongside or remaining alongside during loading operations. This regulation assigns immediate safety authority and responsibility for cargo operations to that officer.