4. To study the following materials problems/specimens (a-e), there is one optical microscopy method that is most appropriate from the following 5 options. Describe which is best, and why, in--25 words or less for each. (10 points total) Bright Field, Dark Field, Interference, Confocal, 3-d slices. (a) The finest fluorescent features visible at the periphery of a living cell. (2 points) (b) The distribution of phases in a block co-polymer. (2 points) (C) The x, y, and z positions of fluorescent microspheres incorporated in a transparent tissue-engineering gel. (2 points) (d) The density of ZnO nanoribbons distributed randomly on a surface. (2 points) (e) The exact thickness of patterned electrodes on an integrated circuit. (2 points)