Rey Received the Highest Grade on Test #1

Multiple Choice

Rey received the highest grade on Test #1. Spencer, who is not Rey, received a grade on Test #1. So, Rey's grade is higher than Spencer's. (r: Rey; s: Spencer; t: Test #1; Gxy: x is a grade on y; Hxy: x is higher than y; Rxy: x received y)
-Which of the following propositions is an immediate (one-step) consequence in F of the given premises?

A) Gst • Rrs • (∀y) {Gyt ⊃ (∀z) [(Rzy • z≠r) ⊃ Hsy]}
B) (∃x) (Gsx • Rxt)
C) (∃x) (Gxt • Rsx)
D) Gat • Rra • (∀y) {Gyt ⊃ (∀z) [(Rzy • z≠r) ⊃ Hay]}
E) Gxt • Rrx • (∀y) {Ryt ⊃ (∀z) [(Gzy • z≠r) ⊃ Hxy]}