A. I was frightened by a bolt of lightning
B. I was frightened by a flash of lightning
Here are two sentences above, and I chose B as my answer, but answer in my book turns out to be A. I found that there are both expressions available in my dictionary, which makes me confused and not know which one is more acceptable. I’m wondering whether there are some nuances in two sentences.
bolt: lightning that appears as a white line in the sky
flash: a bright light that shines for a short time and then stops shining