Select the mismatched pair

Question

$\begin{array}{1 1} (a)\; \text{Adrenaline - Pituitary gland} \\ (b)\; \text{Testosterone - Testes} \\ (c)\; \text{Oestrogen - Ovary} \\ (d)\; \text{Thyroxine - Thyroid gland} \end{array}$