The most solid move. Taking on d4 is also possible although riskier.
1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1b5  3... g8f6  4. e1g1  4... f6e4  5. f1e1  5... e4d6  6. f3e5  6... f8e7  7. b5f1  7... c6e5  8. e1e5  8... e8g8  9. d2d4  9... e7f6  10. e5e1 Both players have a lot of experience in this important position of the Berlin Defense. 10... f8e8  11. c1f4  11... e8e1  12. d1e1 