• Manure Composting Pit Capacity:
• An adult dairy animal unit produces approximately $20\text{--}25\text{ kg}$ dung and $10\text{--}15\text{ kg}$ urine per day ($10\text{--}12\text{ tonnes/year}$).
• When manure is cleared and composted twice a year (6-month storage frequency), the volumetric storage pit capacity required per adult animal unit is $7.5\text{ m}^3$ ($7.5\text{ cubic meters}$).

Correct option: (3) 7.5 cubic meter