In the examples of different rocket shapes, a __ line marks the mid-point of each object's length. A A dotted vertical C C horizontal D D diagonal

The question is asking about the line that marks the midpoint of each object's length in examples of different rocket shapes. The options provided are "dotted," "vertical," "horizontal," and "diagonal." Among these options, the "vertical" line is the most appropriate choice to represent the midpoint of an object's length, especially in the context of rocket shapes. A vertical line divides an object into two equal halves, making it the most suitable choice for marking the midpoint. The other options, such as "dotted," "horizontal," and "diagonal," do not accurately represent the midpoint of an object's length in the context of the question.