The correct answer is C. 3.
The supply of materials for concrete, form work reinforcing and placing of concrete, removal of form work and curing of concrete are all separate activities that need to be completed in order to build a concrete structure. Each of these activities takes time, so they need to be represented on a bar chart as separate bars.
The bar chart shows the start and finish dates for each activity. The length of each bar represents the duration of the activity. The bars are arranged in chronological order, with the earliest activities at the left and the latest activities at the right.
The bar chart can be used to track the progress of the project and to identify any potential delays. If an activity is not completed on time, it can affect the start date of the next activity. This can lead to a delay in the overall completion of the project.
The bar chart can also be used to identify critical activities. Critical activities are those that have no slack time. This means that if a critical activity is delayed, the entire project will be delayed.
The bar chart is a valuable tool for planning and managing construction projects. It can help to ensure that the project is completed on time and within budget.
Here is a more detailed explanation of each option:
- Option A: 1 bar. This option is incorrect because it does not represent the different activities that need to be completed in order to build a concrete structure.
- Option B: 2 bars. This option is incorrect because it does not represent the different activities that need to be completed in order to build a concrete structure.
- Option C: 3 bars. This option is correct because it represents the different activities that need to be completed in order to build a concrete structure.
- Option D: 4 bars. This option is incorrect because it does not represent the different activities that need to be completed in order to build a concrete structure.