I really don’t know that answer but hope u find it
A bond rating is a grade given to bonds that indicates their credit quality. Independent rating services such as Standard & Poor's and Moody's provide these evaluations of a bond issuer's financial strength, or its ability to pay a bond's principal and interest in a timely fashion.
A. Muslim mathematicians introduced algebra into the world
is correct - that is the reason why the number system we use today is the Arabic Numericals.
B. Ibn Sina collected medical knowledge into a book that was used for centuries in Europe
is correct - that books is called The Canon of Medicine.