PREP 39,主语单复数问题

39.  (26509-!-item-!-188;#058&002648)

The Sports Medicine Programs of the Olympic Training
Center, a complex where final tryouts are held for athletes representing the United States
in the Olympics, is geared toward enhancing athletes' performance and toward
their preparation for international competition.

这道题主语应该是单数还是复数呢？ 从 The Sports Medicine Programs来看，好似是复数，但是从后面同位语解释来看，a complex...，既然已经是一个complex综合体，而且前面都有 'a' 形容了，是不是应该说是单数呢，毕竟是一个专有名词，根据同位语的解释来是不是更合适一点呢？

请NN指教。 谢谢