The correct answer is monosaccharides.
When it comes to types of sugars, there are three kinds: monosaccharides, disaccharides, and polysachharides. All of these have Latin prefixes: mono means one, di means two, and poly means more than two, multiple.
So, the simplest out of these sugars are definitely monosaccharides - there is no simpler number than one, and given that monosaccharides contain only one item, it is the correct option here. Some forms of simplest sugars/monosaccharides include glucose, galactose, and fructose.
