Final answer:
The mismatched pair of chemokine and the cells that secrete it is option d) All of the above are correctly matched.
Step-by-step explanation:
The mismatched pair of chemokine and the cells that secrete it is option d) All of the above are correctly matched.
According to the information provided, CCL19 is secreted by lymph-node dendritic cells, CXCL13 is secreted by follicular dendritic cells, and CCL21 is secreted by stromal cells of secondary lymphoid tissues. Therefore, all of the pairs are correctly matched.