The correct option is D Species
Option B: A 'species' refers to a group or a type of animal. For example, 'Homo sapiens' is a species: us humans. The word completes the sentence in meaning, saying that many types of wildlife are becoming extinct. Hence option B is correct.
Option A: 'Specimen' refers to an individual animal or plant used as an example of its species for the purpose of scientific study. A single individual cannot become extinct, as extinction refers to the termination of an entire group or type of that animal.
Option C: Similarly, 'examples' also refers to a few that represent the whole group of wildlife. They cannot be made extinct.
Option D: 'Brands' refers to type, but it isn't used in terms of wildlife. 'Branding' can be done for certain livestock, as they are reared for consumption, but wildlife isn't reared. Hence this word isn't suitable.
Thus, options A, C and D are incorrect.