已知直三棱柱\( ABC{－\text{A}}_{1}{B}_{1}{C}_{1}\)中\( ,\)AC=BC\( ,\)M\( ,\)N分别是\( {A}_{1}{B}_{1},AB\)的中点\( ,\)P点在线段\( {B}_{1}C\)上\( ,\)则\( NP\)与平面\( AM{C}_{1}\)的位置关系是 ( )
A. \( NPC\)平面AMC
B. NP与平面\( AM{C}_{1}\)相交 C. \( NP//\)平面\( AM{C}_{1}\) D. \( NP\)不平行平面AMC1
