Final answer:
Mandibular left first premolar and first molar are the abutment teeth that support a removable partial denture rest, as they are strong enough to provide the necessary support.
Step-by-step explanation:
The abutment teeth that support a removable partial denture rest are essentially the teeth that serve as anchors for the denture. Generally, dentures are designed to replace missing teeth and rely on the remaining natural teeth for stability and support. In the context of the question, the answer would be C. Mandibular left first premolar and first molar. These teeth are typically used as abutment teeth because they are capable of providing the necessary support for the denture due to their size and strength, especially the molars with several pointed cusps used to crush food. The maxillary first molars, maxillary anterior teeth, and maxillary second premolars mentioned in options A, B, and D could also serve as abutment teeth depending on the individual design of the partial denture and the specific needs of the patient.