D) Alan and I baked a strawberry-rhubarb pie. This is the correct option.
The underlined pronoun is in the nominative case. The nominative case is needed before the verb "To bake",
These options are not right.
-A) Yesterday Bob and me worked at the outdoor market. ( The objective pronoun "me" should be replaced by the nominative "I". "To work" needs nominative cases).
B) Last Saturday them and her went to the movies. ( The objective cases "them" and "her" are wrong . "They" and " she" are the correct form.)
C) is that her at the front door? ( This is correct but "her" is in the objective case not in the nominative).
