Which statement about the speed of light is true? a. the speed of light is faster for em waves traveling through a medium. b. no object or em wave can move faster than the speed of light in a vacuum. c. the speed of light changes depending on the motion of the source. d. energy, frequency, and wavelength all affect the speed of light.

Consider a file currently consisting of 200 blocks. assume that the file control block (and the index block in the case of indexed allocation) is already in memory. calculate how many disk i/o operations are required for contiguous, linked, and indexed (single-level) allocation strategies, for each of the conditions listed below. in the contiguous-allocation case, assume that there is not room to grow at the beginning but there is room to grow at the end. also assume that the block information to be added is stored in memory.