What is an alpha and beta linkage in sugars?

The binding of sugars are called glycosidic bonds. These bonds are covalent bonds which, by definition, surround the anomeric carbon of a monosaccharide. Contrary to popular belief, the glycosidic bond does not necessarily have to be between two monosaccharides, just think about what happens in nucleotides, for example, where ribose establishes a glycosidic bond with the nitrogen base. Of course, it can also involve two monosaccharides, as is the case with bonds in oligosaccharides or polysaccharides, but this is not required to happen.

When a glycosidic bond is established, a water molecule is released and is therefore a condensation reaction. The oxygen atom and one hydrogen are released from the anomeric carbon, while the second hydrogen atom is released from the atom to which the anomeric carbon will bind.

Glycosidic bonds are also called alpha or beta bonds. This nomenclature depends on the configuration of the anomeric carbon involved in the glycosidic bond. That is, if the anomeric carbon is in the alpha configuration, the bond is of the alpha type, if it is in the beta configuration, the bond is of the beta type.

For greater understanding, please note the image below.

c. earths continental crust is thicker than its lithosphere.

because, the lithosphere is the outermost layer of the earth/ 100 km thick and is defined by its machanical properties.the lithosphere contains oceanic and continental crust that varies in age and thickness across locations and geologic time. the lithosphere is the coolest layer of the earth in terms of temperature. the term lithosphere should not be confused with the use of "geosphere" which is used to indicate all of earth systems, including the atmosphere, hydrosphere   and biosphere. the surface of the earth can be divided into the continental crust and the oceanic crust.   the continental crust is made mostly of granite while the oceanic crust is made of basalt. the average thickness of the continental crust is 25 miles and the average thickness of the oceanic crust is 5 miles.   three types of rock, igneous, sedimentary, and metamorphic, make up the surface of the earth. that's why 3 option is preferable.