There's a Glitch on that. There are 2 scenario which you should answer "B" . As the Guide says only 95% "A" so there's a 5% for "B". There's a "Very Small Unnoticeable" positioning of the 3rd Mummy Sergeant.
Sorry can't supply you Screenshots since I've graduated already in Tutankhamen (Means I'm already level 90+) But if you just study and focus on it you will get what I mean Focused on their line! Focus on the 3rd mummy at the right if I'm not mistaken his the Sergeant.
Scenarios they say all "A"
1. When the 1st Mummy Lt is too far then that's the time you focus if their line is very straight.
2. When they're in the middle in line.
Take NOTE VERY SMALL UNNOTICEABLE GLITCH but if you do focus on it, you will see that the Sergeant is not inline about a few millimeters away about 1/8 of an inch? hmm hahaha having hard time to explain this but just focus on it and you'll get what i mean. GOODLUCK dude.