In the thymus, thymic stromal cells(TSCs) are interconnected into a network structure. These cells carry a large number of surface molecules and can secrete a variety of thymic hormones and cytokines, which provides a suitable microenvironment for the development and maturation of thymocytes. The types of TSCs include ( ). A: epithelial cell B: macrophage C: dendritic cell D: neutrophil

在容量为N的截面样本中，对每个个体观测了T个时间单位形成的/TSCS数据，其样本容量为（） A: N+T B: NT C: NT D: TN