How many times do you roll damage for Chain Lighting?

Chain Lightning has the following description:

You create a bolt of lightning that arcs toward a target of your choice that you can see within range. Three bolts then leap from that target to as many as three other targets, each of which must be within 30 feet of the first target.

The rules for damage rolls state:

If a spell or other effect deals damage to more than one target at the same time, roll the damage once for all of them. For example, when a wizard casts fireball or a cleric casts flame strike, the spell’s damage is rolled once for all creatures caught in the blast.

Assuming four available targets which of the following is correct?

  • Roll once for damage for all of the targets
  • Roll twice for damage, once for the first target, and once for the three subsidiary targets.
  • Roll damage separately for each targets