Answer:
I'd say D. This test, which my teacher gave me, was really difficult!
I'd say that cause "which my teacher gave me" is a prep and preps make sentences better?
Step-by-step explanation:
Lets check .
A. The test she gave me was really difficult!
o...k...., but who was "she"? not enough detail.
B. My math teacher is the one who gave me a really difficult test!
Ok, i almost chose this too, but, for me its too long. I'm not an English master, btw i hate English. its my worst subject at school, but I wouldn't want to say this long sentence with an explanation point. lol!
C. That was really difficult!
o...k.., but what was "that"?
D. This test, which my math teacher gave me, was really difficult!
o...k... i suddenly wonder why i chose this one, but....it looks right .
so my answer is
D
hope this helps and im probably wrong