• Regional Anesthesia of Mandibular Dentition in Ox: The Mandibular (Inferior Alveolar) Nerve Block is the definitive regional anesthetic technique used to desensitize all lower cheek teeth, dental alveoli, lower jaw bone, and mandibular gums in cattle.
• Anatomical Landmark: Local anesthetic ($15\text{--}20\text{ ml}$ of $2\%$ lignocaine) is deposited at the mandibular foramen on the medial aspect of the ramus of the mandible before the inferior alveolar nerve enters the mandibular canal.

Correct option: (4) Mandibular nerve block

• Osteological Feature of the Equine Pelvis: The Inferior ischiatic spine (spina ischiadica ventralis) is a unique, prominent ventral muscular crest on the ischium characteristic of Equines (horse).
• Anatomical Role: Located on the ventral aspect of the body of the ischium, it provides a robust site of origin for the deep internal obturator and adductor musculature.

Correct option: (1) Equines

Analyzing the statements in relation to Gross and microscopic features of different body systems of domestic fowl:

The correct option is Option 4: Only left ovary is functional.