Sally's Sweet shop is one of the oldest businesses in town to be located on one of the main streets of Millersville.
I agree with David that nothing seems to be wrong, except the missing capital. If Millersville is the town in question, some could argue that it might be more effective for purposes of cohesion to mention the name of the town first and then use the common noun to refer to it:
- Sally's Sweet Shop is one of the oldest businesses in Millersville to be located on one of the main streets (in town). (Actually, I would eliminate "in town" for redundancy reasons.)
Judging from the title of your opening post, your doubt seems to revolve around the use of the infinitive (in this case, the passive infinitive) after a superlative. There's nothing wrong with it, but according to this source I found on the Internet Iranian examiners would prefer, according to your claim, option (1) to (4):
Both (1) and (4) are grammatically correct.
See how in this other version of the same exercise (which is also superior because they revised the inconsistent "Sweet shop" to "sweet shop") the authors realized that there was nothing wrong with option (4) and decided to change the passive to the active infinitive to make it clearly wrong:
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