|Question 16Verbal

Source Texts

Text
The fungus Tricholoma matsutake, commonly referred to as matsutake, is known to establish ectomycorrhizal bonds with certain pine tree species; in many cases, such symbiotic relationships, wherein fungal hyphae make contact with the pine's root system,        extensive networks, which can be used to transport nutrients between trees.
Which choice completes the text so that it conforms to the conventions of Standard English?
forming
A
to form
B
having formed
C
form
D