what conclusion did the researchers from university of california san diego reach regarding the best type of material to use for beach nourishment?

a. boulders should be placed near the water's edge to prevent the current from taking the new sand out to the ocean.

b. sandy areas of a beach should alternate with cement areas to prevent erosion.

c. large, coarse grains of sand should be used since they remain on the beach longer.

d. sand mixed with soil should be used to promote plant growth and prevent erosion.