Self-study
Most of the mines that Moradco operates in the province of Velyena have never violated environmental regulations. █████ ███ ██ ███ ████ █████ ████ ███████ ████████ ██████████ ███ █████ ███ ██ ████ ████ ██ ███████ ████████ █████████████ ████████████
Summary
Most mines that Moradco operates in the province of Velyena have never violated environmental regulations. Every gold mine Moradco operates has at some time violated environmental regulations. 
Notable Valid Inferences
Most of the mines Moradco operates in Velyena are not gold mines.
23.
Which one of the following ██████████ ███████ █████████ ████ ███ ██████████ ██████
a
Moradco operates more █████ ██ ███████ ████ ███ █████ ███████ ████████ ██████
Could be false. We don’t have any information in the stimulus about the number of mines operated by other companies.
b
The total number ██ ████ █████ ████ ███████ ████████ ██ ██████ ████ ███ █████ ██████ ██ █████ ██ ████████ ██ ████████
Could be false. We don’t have any information in the stimulus about the number of gold mines operated by Moradco or the number of mines it operates in Velyena.
c
Most of the ████ █████ ████ ███████ ████████ ███ ███ ███████ ██ ████████
Could be false. Even though we have enough to conclude that most of the mines operated by Moradco in Velyena are not gold mines, it's possible that most of the gold mines operated in Moradco are in Velyena. For example, maybe Moradco has 20 mines in Velyena and 5 of them are gold mines. Perhaps Moradco has a total of 7 gold mines in the world; 5 of those 7 would be in Velynea.
d
Most of the █████ ████ ███████ ████████ ██ ███████ ███ ███ ████ ██████
Must be true, as shown in the diagram below. We know based on the last statement in the stimulus that if a mine has never violated environmental regulations, then that mine is not a gold mine. Since we also know that most of the mines Moradco operates in Velyena have never violated environmental regulations, we can conclude that most mines Moradco operates in Velyena are not gold mines. 
e
Most of the █████ ████ ███████ ████████ ██████████ ███ █████ ███ ███ ████ ██████
Could be false. Moradco could operate mostly gold mines in the rest of the world. Although we know that Moradco's mines that have never violated regulations are not gold mines, it's possible most of Moradco's mines throughout the world have violated regulations. That leaves open the possibility that most of Moradco's mines throughout the world are gold mines.