How is a Block Comment initiated in Java?

A block comment in Java is initiated with the symbol combination "/" and it is terminated with "/". This allows for multi-line comments to be easily included within the code, making it useful for providing extensive explanations, documenting code sections, or temporarily disabling code during development.

Block comments can span several lines, which distinguishes them from single-line comments that are marked with "//" and only apply to the line they are on. Additionally, while /** is a specific form used for documentation comments (which can be processed by tools to generate documentation), it still follows the same initiation with /. The "#" symbol is not recognized as a comment marker in Java. Thus, using "/" appropriately signifies the beginning of a block comment, making it the correct answer.