Answer: a. tRNA
Explanation: The transference RNA is a nucleic acid that participates of the protein synthesis. tRNA is a small RNA with folding as a trefoil. The tRNA has a site where aminoacid is loaded and a anticodon site that is complementary to the codon in the mRNA, ensuring the proper aminoacid sequence in the resulting polypeptide.
"They contain at least one double or triple bond" is true of saturated fatty acid chains. This extra bond is why they are called "saturated", because they had less ability to take on other bonds.
Hormones are a group of chemicals released by exocrine glands

These hormones are directly secreted into bloodstream from where they reach the site.
In DNA the sugar used is called deoxyribose whereas in RNA the sugar is ribose (hence DNA and RNA). The important structural difference between the two types of RNA is that mRNA takes on the shape of a line whereas tRNA has a clover-like shape.