Question

multiple choice question
what are the strong fibrous strings called that attach the av valves to the papillary muscles?
semilunar chords
chordae tendineae
atrioventricular sulci
myocardia

Explanation:

Chordae tendineae are the fibrous strings attaching AV valves to papillary muscles. Semilunar chords are not relevant here. Atrioventricular sulci are grooves and myocardia refers to heart - muscle tissue.

Answer:

B. Chordae tendineae