Atransmission electron microscope would be the best microscope choice to study

The correct answer would be - smaller and ultra-thin structures than a cell.

Explanation:

TEM or the transmission electron microscope is one of an electron microscopy technique that forms an image from a specimen in which electron passes through a substance.

TEM is used to study the specimen that is ultra-thin to be precise it should be less than 100 nm smaller specimen section such as sections or structure smaller than a cell.

Thus, the correct answer is -smaller and ultra-thin structures than the cell.