Which one of the following is known as acceleration stage in the urbanization curve?

1. A

   First stage

   (a) First stage. Northam’s first stage is the initial, slow-urbanisation limb of the S-curve, not the acceleration stage.

2. B

   Second stage

   (b) Second stage. On the classic urbanisation curve the middle limb is rapid, accelerated urban growth as industrialisation pulls labour to towns. That second stage is called the acceleration stage and is the official key.

3. C

   Third stage

   (c) Third stage. The third or terminal stage is levelling-off at high urban shares, sometimes suburbanisation—not acceleration.

4. D

   Fourth stage

   (d) Fourth stage. A fourth limb (counter-urbanisation) appears in some later models; it is not the named acceleration stage.

Summary. Official key is (b) Second stage. The urbanisation curve is an S-shape: slow start, steep middle, flat top. Acceleration is that steep second stage. The first stage is rural-dominant and slow; the third is saturation. Do not mix this with demographic-transition stages, which use similar ordinal labels for births and deaths.