Introduction:
Free float is a term used in project management to identify the amount of time an activity can be delayed without affecting the total float of the succeeding activity. It helps in scheduling and decision-making during the project execution phase. Free float is an important concept in critical path analysis and is used to optimize project schedules.

Explanation:
The correct answer is option 'B' - Free float is mainly used to identify the activities which can be delayed without affecting the total float of the succeeding activity. Let's understand why this is the case:

1. Definition of Free Float:
Free float is the amount of time that an activity can be delayed without delaying the start of any dependent activities. It represents the flexibility in scheduling a particular activity without impacting the overall project timeline.

2. Identifying activities that can be delayed:
By calculating the free float for each activity in a project schedule, project managers can identify the activities that have flexibility in their start and finish dates. These activities can be delayed or rescheduled without causing a delay to the succeeding activities.

3. Focus on succeeding activities:
The main purpose of analyzing free float is to determine the activities that can be delayed without impacting the total float of the succeeding activities. Total float is the amount of time that an activity can be delayed without delaying the project completion date. By focusing on the free float of succeeding activities, project managers can make informed decisions about which activities can be delayed to optimize the project schedule.

4. Optimal scheduling:
By utilizing the information provided by free float, project managers can prioritize activities and allocate resources effectively. They can identify activities with high free float and prioritize them accordingly. This helps in optimizing the project schedule and ensures that critical activities are completed on time.

5. Impact on project timeline:
If an activity with zero free float is delayed, it will directly impact the start of the succeeding activities and may cause a delay in the project timeline. On the other hand, if an activity has a significant free float, it can be delayed without affecting the overall project schedule.

Conclusion:
Free float is a valuable tool in project management that helps in identifying activities that can be delayed without affecting the total float of the succeeding activities. By analyzing free float, project managers can make informed decisions about scheduling and resource allocation, ultimately optimizing the project schedule and ensuring timely completion.