Answer : 3. "slide transition"
Explanation :

1. Animation like effect when you use MS. Transition from one slide to another during a slide show in PowerPoint 2010.

2. First of all, select the slides in which the transition effect is to be added.

3. Click on the Slide Transition option in the Slide Show menu available in the menu bar, which opens the Slide Transition dialogue box.

5. The desired speed of the transition effect is set using the Slow, Medium or Fast option button.