The correct answer is: A. T/B 912
General rules may be modified by specific rules. A specific rule is a rule that applies to a particular situation or group of people. For example, a general rule might be that all students must wear a uniform to school. A specific rule might be that students in the band are allowed to wear their uniforms to school even on days when there is no band practice.
T/B 912 is a specific rule that modifies the general rule that all students must wear a uniform to school. This specific rule allows students in the band to wear their uniforms to school even on days when there is no band practice.
T/D 912 is not a specific rule that modifies the general rule that all students must wear a uniform to school. This specific rule allows students to wear their uniforms to school on days when there is a band practice. However, this specific rule does not apply to students who are not in the band.
T/C 912 is not a specific rule that modifies the general rule that all students must wear a uniform to school. This specific rule allows students to wear their uniforms to school on days when there is a band practice. However, this specific rule does not apply to students who are not in the band, and it does not apply to days when there is no band practice.