To find the product of B and D:
1. Let the four consecutive odd numbers be $A, B, C, D$.
2. Given their average is 42:
_[
_frac{A + B + C + D}{4} = 42 _implies A + B + C + D = 168
_]
3. Since they are consecutive odd numbers, let $A = x$, $B = x+2$, $C = x+4$, $D = x+6$.
4. Substitute into the sum equation:
_[
x + (x+2) + (x+4) + (x+6) = 168 _implies 4x + 12 = 168 _implies 4x = 156 _implies x = 39
_]
5. Therefore, $B = 39 + 2 = 41$ and $D = 39 + 6 = 45$.
6. The product of B and D is:
_[
B _times D = 41 _times 45 = 1845
_]
Therefore, the correct answer is (1) 1845.