Concept:The selection of extension teaching methods is based on practical factors like time, audience size, and farmers' needs.
Explanation:I. Time available for the programme affects method choice.
When time is short, methods like demonstrations or mass media may be preferred.
II. The number of farmers involved is also important.
A method meant for a few farmers may not be effective for a large audience.
III. The agricultural needs of the farmers are essential criteria.
The method must address the specific problems and needs of the farmers.
These factors help extension agents choose among individual, group, or mass methods.
Since every listed criterion contributes to selecting suitable methods, all statements are valid.
Answer:D. I, II and III