Backup/restore is cheapest but has higher RTO/RPO. Warm standby keeps a smaller live environment ready to scale during failover (better RTO). Active-active runs in multiple regions at once (best RTO, often best availability) but is the most complex and expensive.
Expanding on the short answer — what usually matters in practice:
A tiny example (an explanation template):
// Example: discuss trade-offs for "disaster-recovery:-backup/restore-vs-warm-standb"
function explain() {
// Start from the core idea:
// Backup/restore is cheapest but has higher RTO/RPO. Warm standby keeps a smaller live envir
}