The creation of the an army of Turkish warriors to help the Abbasid Caliphs secure their position ultimately led to the conversion of the Turks to Islam, and eventually giving them control over Sunni Islam.
The Abbasid Caliphs were leaders of the "Abbasid Dynasty," which is 2nd of the two great Sunni (Islam) dynasties. Meanwhile, the Seljuk Turks were nomadic people who converted to Islam. Because they were often used as military mercenaries by the Abbasid Caliphate, their power grew, eventually weakening the power of the caliphs, and giving them "control over" Sunni Islam. They revitalized Islamic laws, reorganized the institutions, and provided political stability to the empire.
"bi" means 2: so bi-cameral means with two "cameras" - two chambers, answer B!
a legislative body with only one chamber would be called uni-cameral: "uni" meaning "1", or "unique"