The contents of a particular bottle of shampoo marked as 150 ml are found to be 153 ml at an average, with a standard deviation of 2.5 ml. What proportion of shampoo bottles contain less than the marked quantity? Assume a normal distribution.
a. 0.2192
b. 0.0548
c. None of the others
d. 0.4452
e. 0.1151