下列何神經徑負責維持肌張力及姿勢？(1)紅核脊髓徑(rubrospinal tract)(2)四疊體脊髓徑(tectospinal tract)(3)前庭脊髓徑(vestibulospinal tract)(4)四疊體延髓徑(tectobulbar tract)(A)(1)(B)(2)(C)(3)(D)(4)