Answer
$P(E)=0.1$
Work Step by Step
Event = (Clarice and Dominique}. So, $N(E)=1$.
The sample space: S = {John and Roberto, John and Clarice, John and Dominique, John and Marco, Roberto and Clarice, Roberto and Dominique, Roberto and Marco, Clarice and Dominique, Clarice and Marco, Dominique and Marco}. So, $N(S)=10$.
Using the Classical Method:
$P(E)=\frac{N(E)}{N(S)}=\frac{1}{10}=0.1$
