Which of the Following Is a Correct Short Form Citation

Which of the following is a correct short form citation for page 925 of Mercer v. Davis & Berryman Int'l, Inc., 834 F.2d 922 (1987) , if (1) used in the citation immediately following the full citation and (2) cited in a pleading, motion, or appellate brief?

A) Mercer, 834 F .2d at 922.
B) Id ., at 925.
C) Id ., 834 F .2d at 925.
D) Mercer, 834 F .2d at 922 (1987) .