If haustoria from the fungal partner were to appear within the photosynthetic partner of a lichen, and if the growth rate of the photosynthetic partner consequently slowed substantially, then this would support the claim that .

a. algae and cyanobacteria are autotrophic.
b. lichens are not purely mutualistic relationships.
c. algae require maximal contact with the fungal partner in order to grow at optimal rates.
d. fungi get all of the nutrition they need via the "leakiness" of photosynthetic partners.
e. soredia are asexual reproductive structures combining both the fungal and photosynthetic partners.