You are on a vessel designed to carry compressed gasses in bulk with a cargo of butadiene. Which statement is TRUE?

A
The ullage must be padded with compressed air at a minimum pressure of 2 psig.
B
Silver and copper are prohibited in the parts of valves and fittings in contact with the cargo.
C
The cargo tank may be sampled only when the tank is being filled.
D
The shipping document must specify the exact quantity of butadiene being carried.
E