While on a hike, you notice that several burrs have become attached to your socks. You quickly pull them off. Inside the burr are several seeds. Burrs are produced by certain plants and frequently catch on animal fur (or people's clothing) . After thinking about it, you decide that the burr is a type of ________ that is an adaptation for ________.

a. fruit; seed dispersal
b. leaf; protecting plants from herbivores
c. cambium; seed protection
d. pollen grain; successful pollination