**Core Concept**
The maxillary major connector in removable partial dentures is a critical component that distributes the forces of mastication to the abutment teeth. The rigidity of the connector is determined by its material and design. A less rigid connector is preferred in areas with limited denture-bearing area or where the forces of mastication are high.

**Why the Correct Answer is Right**
The least rigid maxillary major connector is typically made of a resilient material such as a flexible resin or a metal alloy with a high degree of flexibility. This design allows for some degree of deformation under load, thereby reducing the stress concentrations on the abutment teeth. The flexible connector also provides some degree of shock absorption, which can improve the patient's comfort and reduce the risk of denture instability.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a rigid connector made of a metal alloy such as chrome-cobalt or titanium is typically used in areas with high denture-bearing area and low forces of mastication.

**Option B:** This option is incorrect because a rigid connector made of a ceramic material such as alumina or zirconia is typically used in areas with high esthetic demands and low forces of mastication.

**Option C:** This option is incorrect because a semi-rigid connector made of a metal alloy such as chrome-cobalt or titanium is typically used in areas with moderate denture-bearing area and moderate forces of mastication.

**Clinical Pearl / High-Yield Fact**
When designing a maxillary major connector, it is essential to consider the forces of mastication, the denture-bearing area, and the material properties of the connector to ensure optimal distribution of forces and patient comfort.

**Correct Answer: C.**