In the context of Strength of Materials, understanding stress distribution within a member is crucial. The question asks about the relationship between maximum stress and average stress in a member. Let's analyze each option to identify the correct answer:

1. Equal to the minimum stress:
   This option is not correct. In a structural member, minimum stress refers to the lowest stress value, often occurring at certain points, whereas maximum stress occurs at the most stressed points. These two are generally not equal.
2. Less than the average stress:
   This is incorrect. Maximum stress cannot be less than the average stress by definition, as maximum stress represents the peak value.
3. Zero in tension:
   This option is misleading. While it's possible for stress to be zero under certain conditions or at certain points, it does not describe the general relationship between maximum and average stress.
4. Greater than or equal to the average stress:
   This is the correct option. The maximum stress in any member is always greater than or equal to the average stress. The average stress is obtained by dividing the total force by the cross-sectional area, while maximum stress may occur at specific points due to stress concentration or loading conditions.

Let's conclude with an explanation why the correct answer is "greater than or equal to the average stress". In structural analysis, maximum stress is observed at points of stress concentration and varies across a member's section. The average stress is a simplified concept used for basic analysis and does not capture these local variations.

Hence, the maximum stress is always greater than or equal to the average stress in a member.