To solve this problem, we need to determine the correct order of steps in the Polymerase Chain Reaction (PCR).$\newline$PCR is a technique used to amplify DNA sequences and involves three main steps:$\newline \bullet$Denaturation:$\newline$ - This is the first step where the double-stranded DNA is heated to around 94-98°C.$\newline$ - The high temperature causes the hydrogen bonds between the DNA strands to break, resulting in two single strands.$\newline \bullet$Annealing:$\newline$ - In this step, the temperature is lowered to around 50-65°C.$\newline$ - This allows primers to bind or anneal to their complementary sequences on the single-stranded DNA.$\newline \bullet$Extension:$\newline$ - The temperature is then raised to around 72°C, which is the optimal temperature for the DNA polymerase enzyme.$\newline$ - The enzyme synthesizes a new DNA strand by adding nucleotides to the primer.$\newline$Now, let's determine the correct order of these steps:$\newline$1. Denaturation$\newline$2. Annealing$\newline$3. Extension$\newline$This sequence corresponds to Option 4: Denaturation, Annealing, Extension.$\newline$Therefore, the correct option is Option 4.