Ribonucleic acid (RNA) takes part in the expression and regulatio of genes, as cwell as in storing of information.
It's formed by a single strand that pairs with itself and can have a secondary structure that looks like hairpin loops.
Among the more known types of RNA are te messenger RNA (mRNA), wproduced by the transcription of the DNA, that is later translated at the riboomes; the transdfer RNA (tRNA), which takes the amino acids to the ribosome, and ribosomal RNA (rRNA), found in the ribosome (3 is false).
RNA is the way retrovirus stores their genetic information (1 is true), and some types of RNA can act as enzymes and catalyze reactions (2 is true).
This means D) 1 and 2, it's the right answe.