Why can't I use "it is supporter of both ..."?

[Vitaly_]

English Language Proficiency Tests, Advanced Level

ESL/EFL Test #35 "One is always going to lose...", question 6

The government then has to show that it is involved in the whole business of saving and lending and tries to convince everyone that it is ......... of both savers and lenders.

(a) supporting
(b) supporter
(c) supportive
(d) supported

English Language Proficiency Tests, Advanced Level

ESL/EFL Test #35 "One is always going to lose...", answer 6

The government then has to show that it is involved in the whole business of saving and lending and tries to convince everyone that it is supportive of both savers and lenders.

Correct answer: (c) supportive

Your answer was: incorrect
The government then has to show that it is involved in the whole business of saving and lending and tries to convince everyone that it is supporter of both savers and lenders.
_________________________

Why can't I use "it is supporter of both ..."?
Oh-oh, maybe if I use a noun it needs an article?

Vitaly

[Sara_h]

Hi there,
I also did this test and I didn't choose the answer d"supporter" because of 2 reasons:
1.'supporter' is a countable noun so it requires either "a"
or "the" and in the sentence there is no article
2.the first part of the sentece says: "the government ... is involved"...so it is a logical continuation "tries to convience that is... supportive Can you see the similarity?
I hope that will help you a bit

[Lost_Soul]

"...it is supportive of both savers and lenders"

Could anyone rehash it... I seem not to be able to grasp the meaning...

thanks

[Yankee]

The government gives support to and/or encourages both those who save money and those who borrow money.