Why is oceanic crust continually recycled via subduction?

Why is oceanic crust continually recycled via subduction?

• A. Oceanic crust forms at mid-ocean ridges and sinks back into the mantle at subduction zones, recycling material into magma
• B. Oceanic crust forms at trenches and never sinks
• C. Continental crust forms at mid-ocean ridges
• D. Subduction zones recycle both continents and oceanic crust equally

Answer: (B)