Spotted Salamanders Lay Eggs in Gelatinous Masses on Twigs Partially

Spotted salamanders lay eggs in gelatinous masses on twigs partially submerged in small ponds or vernal pools. Associated with the eggs, scientists have found a species of alga living in a mutualistic relationship with the developing eggs. What benefit does the salamander receive from this relationship?

A) The salamander eggs are better camouflaged.
B) The salamander embryos receive an increased oxygen supply.
C) The salamander embryos receive an increased carbon dioxide supply.
D) The salamander embryos receive an increased nitrogen supply.