Correct option is A
Air voids are indeed much larger than capillary pores. Capillary pores are very small, typically in the range of micrometers, while air voids can be significantly larger, ranging from a few millimeters to centimeters, depending on their formation.
Micro cracks: Generally smaller than air voids, though they can be larger than capillary pores.
Blow holes: Larger voids that occur due to trapped air or gases during the casting process, but not as commonly referenced in this context.
Macro cracks: Larger than capillary pores, but air voids are generally considered larger.
Therefore, the correct answer is (a) Air voids.
