When two objects at different temperatures are placed in contact, heat will always flow from the hotter object to the cooler object until thermal equilibrium is reached. In your case, one block is at 160°C (hotter) and the other is at 141°C (cooler).
So, the heat will flow from the block at 160°C to the block at 141°C. Therefore, the correct option would be:
a (heat flowing to 160°C)
This option implies that heat is flowing away from the 160°C block towards the block at 141°C.