Chess Opening Theory/1. d4/1...Nf6/2. c4/2...Nc6/3. Nf3

=Black Knights Tango=

3. Nf3
With this common reply to the Tango White prevents Black from the central break e5. Black now has a choice of supporting a d5 or a e5 advance.

Theory table
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'''1. d4 Nf6 2. c4 Nc6 3. Nf3'''