Convert each of the following decimals into a fraction in simplest form.
a. (i) The price of one pen is Rs 3.125. Express this price exactly as a fraction of a rupee.
b. (ii) The probability that a machine produces a defective bolt is 0.4. Write this probability as a rational number.
c. (iii) During an experiment a student records the reading 2.237. Express this reading as a fraction.