1.Which one of the following charts represents a probability distribution(5points):

• X P(x)A
• 0 -0.1
• 1 0.1
• 2 0.4
• 3 0.6

• X P(x)B
• 0 0.3
• 1 0.2
• 2 0.1
• 3 0.35

• X P(x)C
• 0 0.1
• 1 0.2
• 2 0.4
• 3 0.1

• X P(x)D
• 0 0
• 1 0
• 2 2
• 3 0