Step 1: Use the two best known names.
Rohu is the best known carp of India, and the Sanskrit name rohita points to it. Rohita appears in Manusmriti as an allowed fish. So A must be in the answer.
Step 2: Cut by A.
Option 4 does not contain A, so it is removed.
Step 3: Look at the extra letters.
Options 2 and 3 add D (Girai), and option 3 also adds C (Jhinga). Neither Girai nor Jhinga is named in the permitted list of verse 5.16.
Step 4: Confirm B.
Pathina, the pathen fish, is named with rohita in the same verse, so B belongs in the answer along with A.
Step 5: Conclude.
Option 1 has exactly A and B with nothing extra.
Step 6: Memory aid for the verse.
Verse 5.16 can be remembered through its first two names, pathina and rohita. A student who knows only these two can already pick option 1. The other names in the verse, rajiva, simhatunda and sashalka, are not in the question, so they cannot create confusion. Jhinga and Girai are not in the verse at all, which is why the shorter option with only A and B is the right one.
Final Answer:
Option 1 is correct.
\[ \boxed{\text{Option 1}} \]