A qualitative phase diagram of a substance is shown in the figure below. Choose the correct option from the following statements.

• Correct answer
  A

  The liquid to vapour phase transition of the substance is not possible at STP.
• B

  When two blocks of the substance are pressed together and released, they form a single solid block.
• C

  All the three phases of the substance cannot coexist.
• D

  The substance can be solidified only at high pressure.

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