Which of the following is the correct statement w.r.t. the cells that are much thickened at the corners due to the deposition of cellulose, hemicellulose and pectin?

• A

  They occur in layers below the epidermis (hypodermal in postition) in most of the aerial parts of dicotyledonous plants.

• B

  These cells are always found as a homogeneous layer.

• C

  They are usually dead and without protoplasts.

• D

  These are commonly found in the fruit walls of nuts.