Which query is a correctly formatted nested search?

A.
“energy policy” w/5 (“alternative energy” w/10 “solar power”)

B.
“energy policy” w/5 [“alternative energy” w/10 “solar power”]

C.
{“energy policy” w/5 “alternative energy” w/10 “solar power”}

D.
“energy policy” w/5 “alternative energy” w/10 “solar power”