Final answer:
The oldest clade according to the attached cladogram is hominidae. Therefore, the correct option is D.
Step-by-step explanation:
According to the attached cladogram, the oldest clade is hominidae. The cladogram represents the evolutionary relationships between different groups of organisms. In this case, the clades are represented by the branches on the cladogram. The oldest clade is the one that diverged earliest from the common ancestor.
In the given options, only hominidae is included in the cladogram and therefore, it is the oldest clade.
Therefore, the correct option is D.