The CBI is investigating a dangerous gang of three criminals. The criminals are Donga, Tirudan and Daaku. The investigation team consists of Pradyuman, Daya, Fredricks, Salunkhe, Tarika and Purvi. Each criminal is to be investigated by exactly two investigators, and each investigator investigates exactly one criminal. The investigation is to be conducted subject to the following constraints: Pradyuman and Daya do not investigate the same criminal. Fredricks and Salunkhe investigate the same criminal. If Fredricks investigates Tirudan, then Tarika must investigate Daaku. Given these constraints, which of the following could be the acceptable assignment(s) of investigators to potential criminals?