Let's break down the code:

WM = ['b' * x for x in range(4)]
print(WM)

• The list comprehension ['b' * x for x in range(4)] iterates over the range of numbers from 0 to 3.

• In each iteration, it multiplies the string 'b' by the current value of x.

• For x = 0: 'b' * 0 results in an empty string ''.

• For x = 1: 'b' * 1 results in 'b'.

• For x = 2: 'b' * 2 results in 'bb'.

• For x = 3: 'b' * 3 results in 'bbb'.

So, the list WM will be: ['', 'b', 'bb', 'bbb'].

Answer: (A) ['', 'b', 'bb', 'bbb'].