The correct answers are B) reduced open space, and C) reduced timber supply.
The disposal of the dead in some religions puts a strain on the environment. The potential problems that may be caused by these practices are reduced open space and reduced timber supply.
The disposal of the dead is the way people deal with the remains of people who are dead. As the body tends to decompose, there is the need to bury or cremate it. Every religion has its own practice to deal with the dead, but some put a strain on the environment. Christians and Jews tend to bury the body in cemeteries or cremate the body and then the family keep the ashes or throw it away in nature.
In some countries, the space allocated for cemeteries is a problem because these places are full. That is why North American and European countries are recommending cremation of the body.