We have to check the images that are symmetrical about the given line.
\(\bullet\) A is not symmetrical about the line shown. Both halves of shape A are not the same. Both halves are not mirror halves, and they can’t exactly overlap each other.
\(\bullet\) B is not symmetrical about the line shown. Both halves of shape B are also not the same. Both halves are not mirror halves, and they can’t exactly overlap each other.
\(\bullet\) Both halves of shape C can overlap each other when folded along the given line. Both halves are mirror halves. So, shape C is symmetric about the line.
Hence, C is the correct option.