Houses of the Harappan cities were generally built with rooms arranged around a:

Harappan houses were usually built with rooms arranged around a central open courtyard.

About Harappan houses:

• Most houses were made of baked (burnt) bricks of standard size, or of sun-dried mud bricks in some places.
• The bricks were laid in a "English bond" pattern, with alternate layers of headers and stretchers, which made the walls strong.
• The ratio of the length, breadth and thickness of the bricks was usually 4:2:1, which shows a high degree of standardisation.

Features of houses according to NCERT:

• The courtyard was the centre of the house, used for activities such as cooking and weaving, especially in hot and dry weather.
• There were no windows in the walls facing the street, perhaps for privacy.
• The main entrance did not give a direct view of the interior or the courtyard.
• Many houses had their own bathroom, paved with bricks, with drains connected through the wall to the street drains.
• Some houses had stairs leading to a second storey or the roof.
• Many houses had their own wells; it is estimated that Mohenjo-daro had about 700 wells.

Town planning:

• Streets were laid out in a grid pattern and crossed at right angles.
• Covered drains ran along the streets, with inspection holes at intervals.
• Houses were of different sizes, from small one-room houses to large houses with many rooms, which suggests differences in wealth.
• The "lower town" was the main residential area.

Importance:

• NCERT notes that the attention to planning, drainage and household sanitation is unique among ancient civilisations.
• Even in modern times, the courtyard house is common in many parts of India.

Why not the other options?

• ✗Watchtowers were part of fortifications, not houses.
• ✗Large water tanks were public structures, not part of ordinary houses.
• ✗Good to know
• ✗Harappan houses did not have temples inside them.