The rule [(PrightarrowQ)land(QrightarrowR)]Rightarrow(PrightarrowR)[(P \\rightarrow Q) \\land (Q \\rightarrow R)] \\Rightarrow (P \\rightarrow R)[(PrightarrowQ)land(QrightarrowR)]Rightarrow(PrightarrowR) is known as:
Hypothetical Syllogism
Conjunction
Modus Ponens
Disjunctive Syllogism