The numbers increase by 1 each step.<br><br>
&bull; 3996, 3997, 3998, ___ , ___ , ___<br>
&bull; 3998 + 1 = 3999<br>
&bull; 3999 + 1 = 4000<br>
&bull; 4000 + 1 = 4001<br><br>
Final Answer: A = 3999, B = 4000, C = 4001