The correct answer is (a) 2:30.
When an object is placed in front of a plane mirror, the image formed is the same size as the object and is located behind the mirror at the same distance from the mirror as the object is in front of the mirror. The image is also laterally inverted, which means that the left side of the object appears on the right side of the image and vice versa.
In the case of a clock, the hands of the clock will appear to be moving in the opposite direction when viewed through a plane mirror. This is because the image of the hands is formed behind the mirror, and the hands of the clock are actually moving in the forward direction.
When the clock shows the time of 8:00, the image of the clock will show the time of 2:30. This is because the hour hand of the clock will appear to be moving from 8 to 9, while the minute hand of the clock will appear to be moving from 12 to 1.
The other options are incorrect because they do not represent the correct time that would be shown by a clock when viewed through a plane mirror.