The correct answer is: b) Fluid and subject to change.
Territorial boundaries between chiefdoms were often fluid and subject to change. This was due to a number of factors, including the fact that chiefdoms were often not centralized states, but rather loose confederations of smaller groups. As a result, the boundaries between chiefdoms could shift as different groups gained or lost power. Additionally, the boundaries between chiefdoms were often not clearly defined, as they were often based on factors such as kinship, language, or custom, rather than on physical features such as rivers or mountains. As a result, the boundaries between chiefdoms could be disputed and could change over time.
Option a) is incorrect because territorial boundaries between chiefdoms were often not clearly defined. Option c) is incorrect because territorial boundaries between chiefdoms were not determined by British administrators. Option d) is incorrect because territorial boundaries between chiefdoms were not based on religious divisions.