(A) The sample space $S$ for throwing two dice contains $36$ outcomes.
Event $A$ (even number on the first die) is given by:
$A = \{(2,1), (2,2), (2,3), (2,4), (2,5), (2,6), (4,1), (4,2), (4,3), (4,4), (4,5), (4,6), (6,1), (6,2), (6,3), (6,4), (6,5), (6,6)\}$
Event $B$ (odd number on the first die) is given by:
$B = \{(1,1), (1,2), (1,3), (1,4), (1,5), (1,6), (3,1), (3,2), (3,3), (3,4), (3,5), (3,6), (5,1), (5,2), (5,3), (5,4), (5,5), (5,6)\}$
Two events are mutually exclusive if their intersection is an empty set,i.e.,$A \cap B = \phi$.
Since the first die cannot be both even and odd simultaneously,there are no common outcomes between $A$ and $B$.
Thus,$A \cap B = \phi$.
Therefore,the statement is true.