Harish performed two different experiments I and II. In experiment I, he provides a substance 'X? with some heat. He found out that a sudden reaction takes place to form heat, light, and sound. In experiment II, he provides heat to a substance 'Y?. He found out that when Y bums, only heat and light are produced. Experiment I represents an example of __i__, and experiment II represents an example of __ii___. The information in which alternative completes the given statement?

• A.  i-Explosion, ii-Rapid combustion
• B.  i-Explosion, ii-Sportaneous combustion
• C.  i-Spontaneous combustion, ii-Explosion
• D.  i-Rapid combustion, ii-Spontaneous combustion