Concept:
Harappan art and architecture include town planning, seals, drainage systems, brick structures, sculpture, pottery, and architectural materials.
The Great Bath and Pashupati Seal are among the most famous remains of the Harappan Civilization.
Step 1: Check Great Bath.
The Great Bath is one of the most important structures found at Mohenjo-daro.
It is associated with Harappan architecture.
So, A is correct.
Step 2: Check Pashupati Seal.
The Pashupati Seal was found at Mohenjo-daro and belongs to Harappan art.
So, B is correct.
Step 3: Check building materials.
Bitumen and gypsum were used in Harappan construction.
Wet lime mortar is also associated with ancient construction practices.
So, C and D are correct.
Step 4: Check Deedarganj Yakshini.
Deedarganj Yakshini belongs to the Mauryan period, not the Harappan Civilization.
So, E is incorrect.
Therefore, the correct statements are:
\[
A,\ B,\ C,\ D
\]
Hence, the correct answer is:
\[
\boxed{\text{(B) A, B, C and D only}}
\]