1. Let the 9 terms of the GP be $a, ar, ar^2, ar^3, ar^4, ar^5, ar^6, ar^7, ar^8$

2. The 5th term is given as 2. Since the 5th term is $ar^4 = 2$

3. We need the product of all 9 terms: $P = a \cdot ar \cdot ar^2 \cdot ar^3 \cdot ar^4 \cdot ar^5 \cdot ar^6 \cdot ar^7 \cdot ar^8$

4. Add the powers of $r$: $P = a^9 r^{0+1+2+3+4+5+6+7+8} = a^9 r^{36}$

5. Rewrite this as: $P = (ar^4)^9$ because $a^9 r^{36} = (ar^4)^9$

6. Substitute $ar^4 = 2$: $P = 2^9 = 512$

7. Therefore, the product of the 9 terms is $\boxed{512}$

8. Option check:

   • A: $256$ ❌
   • B: $512$ ✅
   • C: $1024$ ❌
   • D: none of these ❌

Hence, the correct option is B.