This study is about whether Vitamin D helps children with wet OAB (Overactive Bladder). Overactive Bladder causes frequent urination and accidents. The study compares three treatments:

• Standard behavioral therapy with Vitamin D.
• Standard behavioral therapy with solifenacin (a medicine that helps relax bladder muscles).
• Standard behavioral therapy alone.

To join, children must be at least 5 years old, have a confirmed diagnosis of wet OAB, and low Vitamin D levels. The study will last a few weeks, and participants will follow one of the treatments above. Researchers will check how often kids urinate, their quality of life, and satisfaction with the treatment.

• Participation involves taking Vitamin D daily, solifenacin, or neither.
• Researchers need to collect data from participants, like urination diaries, for 7 days.
• Children with other serious diseases or ongoing treatments can't join.