What is a distinctive feature of the structure of each Risalah in Risalah Ramadaniyya?

A. A lack of commentary or context for the quoted texts
B. A single theme that is explored throughout the epistle
C. A focus solely on the authority of the dāʿī and the daʿwa dignitaries
D. A division into two sections: supplication and eulogy, and a variety of topics
Answer: 