Step 1:
Puranic literature indeed mentions:
\[
12 \text{ Jyotirlingas}
\]
Hence, Assertion (A) is correct.
Step 2:
Jyotirlingas symbolize the radiant form of Lord Shiva, not Lord Vishnu.
Thus, Reason (R) is incorrect.
Step 3:
“Jyoti” means divine light and “Linga” refers to Shiva.
Step 4:
Therefore:
\[
\boxed{\text{A is correct but (R) is not correct}}
\]
Hence, the correct answer is:
\[
\boxed{\text{(3)}}
\]