Tendons through which muscles are connected to bones are tightly compacted bundles of which one of the following long fibrous protein?

The correct option is A Fibrin

A. Fibrin is a type of insoluble protein which is formed from fibrinogen. A clot is formed when fibrinogen of plasma is converted to fibrin. The polymerized fibrin together with platelets forms a hemostatic plug or clot over a wound site.

B. Collagen is a type of connective tissue that consists of long unbranched, soft elastin fibres of tropocollagen.

C. Elastin is a type of connective tissue that consists of less numerous branched, flexible elastic fibres.

D. Cellulose is a polysaccharide made of glucose subunits.

Tendons through which muscles are connected to bones are made up of collagen.

So, the correct answer is 'Fibrin'.