씁니다->이용합니다 The answer using 씁니다 is wrong. It should answer with 이용합니다.
I was just about to post this.
For anyone wondering:
씁니다 - to use something
이용합니다 - to make use of something
"I use public transportation often" works too.
So, 쓰다 means "write", "wear", and now "use"...
among some dozen more other meanings :)
씁니다 ㅡㅡㅡㅡ탑니다 이용합니다