Which words in the sentence are the complete noun clause?

the big green parrot speaks to whoever comes into the house.

a. whoever comes into the house
b. the big green parrot speaks
c. into the house
d. the big green parrot speaks to whoever

Among the options provided above, the noun clause is:

A.    whoever comes into the house

Noun clause is introduced by words such as whoever, whomever and others. It is a dependent clause which can act as a noun, subject, direct or indirect objects, predicate nominatives, and preposition objects. 

the correct answer is a. how to make proposal that works.

indeed, the register is quite formal and the tone is especially objective as it avoids the use of the first and second person singular (i, you) and opts instead for the third person plural which is more impersonal and focuses on the data and the argument that is being developed by the author. the formality adds the impression of respectability to the work and the impersonality adds objectivity to it.

tree and the cat in the tree