Final answer:
The correct apparatus needed to find the density of both the water and the concrete block is Option C: a Balance for measuring mass, a Measuring Cylinder for measuring volume of water, and a Ruler for finding volume of the concrete block.
Step-by-step explanation:
To find the density of both the water and the large, regularly shaped concrete block, you would need to use Option C: Balance, Measuring Cylinder, and Ruler.
The balance is used to measure mass of the concrete block and water, the measuring cylinder is used to measure volume of water, and the ruler is used to measure the dimensions of the concrete block to find its volume (given it's regularly shaped, we can use geometric formulas). The density can then be calculated by dividing the mass by the volume.
Learn more about Density Measurement