Assertion (A) : Alkali metals are soft and have low melting and boiling points.Reason (R) : This is because interatomic bonds are weak.

• A

  Both (A) and (R) are not true
• B

  (A) is true but (R) is not the correct explanation of (A)
• C

  (A) is true but (R) is false
• Correct answer
  D

  Both (A) and (R) are true and (R) is the correct explanation of (A)

Hence, the correct answer is option: 'D'.