(B) The walk around Saxe-Coburg Square
is the key event in story which leads to Holmes' solution of the case.
Sensitivity to the sound structure of words
It’s the ability to recognize and work with sounds in a spoken language.
A complex character has multiple or conflicting motivations. (I think I'm not so sure)
Harriet Tubman uses ethos to have the readers trust her and it helps make her an author you can trust. Ethos is when an author tries to convince the reader that they are a reliable source. So she uses ethos for her rhetorical appeal.
Hope that helps