Beginning in the 1950s, Navajo Nation legislator Annie Dodge Wauneka continuously worked to promote public health; this.

_ effort involved
traveling throughout the vast Navajo homeland and writing a medical dictionary for speakers of Diné bizaad, the Navajo language.
Which choice completes the text with the most logical and precise word or phrase?
A) impartial
B) offhand
C) persistent
D) mandatory