Facts: A delivers a boiler to the house of his customer K. He buys a control computer from manufacturer B, which is used for heating the boiler. A wrongly connects the control computer to the heating system. While K is on winter vacation, the control computer deactivates the heating, resulting in temperatures of -10°C in K’s house. As a result, the water in the water pipes in K’s house freezes and the pipes start to leak. Three days later, temperatures in K’s house are around +5°C, the cellar is flooded and the renovation costs for the cellar and the water pipes amount to EUR 50,000.

Question: What claims does K have against A and B?