`ADPrarrATP` system was found by Lipmann in

Options

A. 1940
B. 1950
C. 1960
D. 1970

Answer

To answer the question about when the ADP to ATP system was found by Lipmann, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the ADP-ATP System**: The ADP-ATP system refers to the process by which adenosine diphosphate (ADP) is converted to adenosine triphosphate (ATP). This process is crucial for energy transfer within cells.

2. **Historical Context**: The discovery of ATP itself occurred in 1929 by Karl Lohmann and his colleagues. This sets a timeline for when ATP was recognized as an important molecule in cellular processes.

3. **Lipmann's Contribution**: Albert Lipmann proposed that ATP is the main energy transfer molecule in cells in the year 1940. This was a significant contribution to biochemistry, as it established ATP as a key player in energy metabolism.

4. **Mechanism of ATP Production**: Lipmann's work also included the understanding of how ATP is produced, particularly through the addition of an inorganic phosphate to ADP, which is part of the chemiosmotic mechanism occurring in the inner mitochondrial membrane.

5. **Conclusion**: Based on the historical context and Lipmann's contributions, we can conclude that the ADP-ATP system was found by Lipmann in the year 1940.

### Final Answer:
The ADP-ATP system was found by Lipmann in **1940**.