The trip led to an argument between Helen and ? a. I. b. me. (A)

Question

It was ? who demanded an apology from the newspaper. a.we b.us (B)
We appreciated ? writing a personal letter to explain his stand on the issue. a.his b.him (B)
The most outspoken critics were my sister and ? a.I. b.me. (A)

Answer 1

Please list just your answers for each one.

Answer 2

1. he trip led to an argument between Helen and ? a.I b.me (A)
2. It was ? who demanded an apology from the newspaper. a.we b.us (B)
3. We appreciated ? writing a personal letter to explain his stand on the issue. a.his b.him (B)
4. The most outspoken critics were my sister and ? a.I b.me (A)

Answer 3

1. No
2. No
3. No
4. Yes

Study these:
http://grammar.ccc.commnet.edu/grammar/cases.htm (Scroll down a bit and notice in the chart which pronouns can correctly be used as subjects and which as objects.)
and
http://grammar.ccc.commnet.edu/grammar/gerunds.htm#possessive