Which of the following types of sampling is most likely to have bias?

Snowball sampling is most prone to bias because existing participants recruit similar others.

Simple random sampling gives every unit an equal selection chance, minimising bias.

Stratified random sampling samples randomly within defined subgroups.

Cluster random sampling randomly selects whole groups then studies their members.

Snowball sampling is a non probability method used for hard to reach populations.

Its reliance on referral chains makes the resulting sample unrepresentative.