This is a most popular example of Lamarck

The correct option is Both (b) and (c).

Lamarck's theory of evolution, also known as Lamarckism or the theory of inheritance of acquired characters, proposes that organisms undergo physical changes during their lifetime in response to their environment, and these acquired traits are passed on to their offspring. This theory is primarily based on two principles: the "use and disuse of organs" and the "inheritance of acquired characteristics".

Let's examine how both options (b) and (c) serve as classic examples of Lamarck's theory:
1. African Giraffe (Use of organs): Lamarck explained that the ancestors of giraffes had short necks and forelimbs. As the ground vegetation became scarce, they had to stretch their necks and forelimbs to feed on leaves high up on trees. Due to this continuous stretching and use, their necks and legs gradually became longer. This acquired trait was inherited by successive generations, eventually leading to the modern long-necked giraffe.
2. Snakes (Disuse of organs): According to Lamarck, the ancestors of snakes possessed limbs. To protect themselves from predators and to hunt prey, they started creeping on the ground and burrowing into narrow holes. In this lifestyle, limbs were not useful and hindered their movement. Due to continuous disuse over generations, the limbs gradually reduced in size and eventually disappeared completely.

Therefore, both the elongation of the giraffe's neck and the loss of limbs in snakes are highly popular examples used to illustrate Lamarckism, making Both (b) and (c) the correct choice.