The correct answer is B) snatch block. A snatch block is a type of block that can be opened at the hook or shackle end to receive a bight (loop) of the line. This allows the line to be quickly inserted or removed from the block without having to reeve the entire line through. This feature makes snatch blocks useful for applications where the line needs to be easily and quickly diverted or redirected. The other answer choices are incorrect because a bight block is a type of block used to create a bight in a line, a heel block is used to guide a line around a sharp corner, and a gin block is a type of block used in logging operations, not a block that can be opened to receive a bight of line.