The correct answers are options are B and E.
The excerpts that use language to build an informal tone are:
B. "At dusk, fingertips numb, Ona tore sheets of bark from the tree, building herself a papery cradle on the uneven floorboards where she could sleep for years."
- The use of "fingertips numb" and the description of building a "papery cradle" adds a personal and informal touch to the narration.
E. "After rinsing each dish in the creek, she dried them with her shirtsleeve and put them back in place."
- The mention of rinsing dishes in the creek and drying them with a shirtsleeve conveys a practical and informal approach to daily tasks.
So, the correct answers are options are B and E.