下列神經路徑中，何者是直接運動路徑(direct motor pathway)？(1)紅核脊髓徑(rubrospinal tract)(2)前庭脊髓徑(vestibulospinal tract)(3)前皮質脊髓徑(anterior corticospinal tract)(4)外側網狀脊髓徑(lateral reticulospinal tract)(A)(1)(B)(2)(C)(3)(D)(4)