Select the non-probability sampling techniques. Choose the correct answer from the options given below.

Snowball sampling and purposive sampling are the non-probability techniques among the four.

In non-probability sampling units are chosen by judgement or accessibility, not by random chance.

Snowball sampling recruits later respondents through referrals from earlier ones.

Purposive sampling selects cases deliberately for their relevance to the research aim.

Systematic sampling picks every kth unit from a frame, which is a probability method.

Simple random sampling gives every unit an equal, known chance of selection, again a probability method.