Answer:
Explanation:The words establish the author of the article as an expert on cookstoves.
The words imply that cookstoves are something negative.
The words show that people in developing countries dislike cookstoves.
The words hint that cookstoves are not as bad as many people believe they are.
B. is the BEST because it gives the flexibility of theme ideas for courage.
C. is very specific on climbing mountains as the only way to learn about courage.
A and D are criticising courage.