Kate as well as her family members _______ on the spot when Randy’s wedding took place.

句子中的主语是Kate as well as her family members，其中的as well as连接的两个部分做主语时，谓语动词的单复数形式要与前面的主语保持一致，即与Kate保持一致，采用单数形式。同时，根据句子中的时间状语when Randy’s wedding took place，可知句子时态为一般过去时，因此正确答案为A，表示“过去存在状态”。