Ravi takes three substances X, Y, and Z. On heating these substances he observes that they bum at different temperatures. He finds out that X catches fire on little heating, while Y and Z do not catch fire. On further heating of Y and Z, he observes that Y catches fire, while Z does not. The correct arrangement of X, Y, and Z in order of their increasing ignition temperatures is

• A.  \[X<Y<Z\] 
• B.  \[Z<Y<X\]
• C.  \[Z<X<Y\]        
• D.  \[Y<X<Z\]