On What Grounds Did Chittka & Niven (2009) Argue That

On what grounds did Chittka & Niven (2009) argue that brain size is unlikely to be related to social intelligence?

A) Many insects live in large-scale social networks
B) Brain size is related primarily to the extent of tool use
C) Many animals with large (relative) brain size have low social intelligence.
D) Brain size and mirror-self recognition are unrelated.