Answer:
(1) single covalent bonds, only.
Step-by-step explanation:
Remember that saturated hydrocarbons are those molecules that form single covalent bonds. And they are known as saturated because they contain more hydrogen than an unsaturated hydrocarbon, so based on this logic the answer would be that in saturated hydrocarbons, carbon atoms are bonded to each other by (1) single covalent bonds, only.