Which statement about entry into a space that has been sealed for a long time is TRUE?

A
A tank that has been used to carry hazardous liquids should be tested for oxygen content, toxicity, and explosive gases.
B
You can safely enter the space without a breathing apparatus if the oxygen content exceeds 14%.
C
The natural ventilation through the installed vents is sufficient to provide the proper oxygen content.
D
The heat of the sun on upper ballast tanks, such as in a bulk carrier, may generate carbon monoxide.
E