In most cells, (mRNA, a protein, DNA) directs the production of a
molecule of (mRNA, a protein, DNA)
which then enters a ribosome. The
ribosome produces the final product, (mRNA, a protein, DNA)
Retroviruses do the opposite. They use the enzyme reverse
transcriptase to use a template of (mRNA, a protein, DNA)
to produce (mRNA, a protein, DNA)

The correct answer is b

Glucose, also called grape sugar, blood sugar or corn sugar, is among the simplest and one of the primary naturally occurring sugars. produced naturally by plants as the primary photosynthesis product, it is heavily used by living beings as a main energy source and is necessary for cellular respiration. chemically, it is a monosaccharide carbohydrate and serves as a building block for complex sugars like starch.