3. Let $a, b, c$ be different numbers, proposition: (1) If $a, b, c$ form a geometric sequence, i.e., $b^{2}=a c$, and $a c>0$; (2) If $a, b, c$ are any three terms of some arithmetic sequence, then they cannot be any three terms of some geometric sequence; (3) If $a, b, c$ are any three terms of some arithmetic sequence, and they are all irrational numbers, then the common difference must be an irrational number, the incorrect ones are ( ).
A. 3
B. 1
C. 0
D. 2
3. A.

For (1), it is correct only in the range of real numbers; For (2), it is incorrect, for example $1,2,4$; For (3) it is also incorrect, such as $1+\sqrt{2}, 2+\sqrt{2}, 3+\sqrt{2}$.