I was doing one of the Whizlabs sample exam (Practice Test 3, Q20). I've attached the question as a screenshot.
It says the answer is 'C' but I'm thinking the space inside the final ending tag would mess things up.
Also I would have thought 'A' would be the correct answer and it's a correct usage of tags (the indentation may be to throw off the user).
The bit I've highlighted in red seems (I think) to hint at the fact that the question maybe should have been something like '..which below
shows the correct syntax of nested tags...'