How many of the carbon-carbon bonds in the compound have staggered conformers that are all equally stable?

In stereoisomers, there are two classifications: staggered and eclipsed conformations. The staggered conformation is when the bonds are not symmetric. Eclipsed is less stable than the staggered conformation. It actually depends on the compound. For example, the ethane is drawn in the staggered conformation, which only has 1 C-C single bond.