Final answer:
The correct replacement engine is 126L02-1025B, while the other engines mentioned are not suitable replacements. It is recommended to repair the engine with parts if possible.
Step-by-step explanation:
The correct replacement engine for the model 12F702-0507A is the 126L02-1025B. The other engines mentioned, 126L02-1018C and 126L02-0507D, are not suitable replacements. Instead of replacing the engine, it is recommended to repair it with parts if possible.