Pick up the correct statement from the following:

• The float may be positive, zero or negative
• If the float is positive and the activity is delayed by a period equal to its total float, the completion of project is not delayed
• If the float of an activity is negative, delay in its performance is bound to delay the completion of project
• If the float of an activity is zero, the activity is critical and any delay in its performance will delay the whole project
• All the above.