Answer:
A.
Explanation:
1. the required probablilty is: P=(number_of_even_numbers)/(number_of_all_the_numbers);
2. according the condition the number of all the numbers is 10; the number of even numbers is 5 (they are: 2; 4; 6; 8; 10), then
3. P=5/10=0.5 (option 'A').