The correct answer is (a) True
Explanation: In optical biosensors, there are two main areas in which development can happen. Firstly, the measurement of changes in light absorption between the reactant and product of a reaction. These use colorimetric test strips to measure the change. These strips are single-use cellulose pads which are impregnated with enzyme and reagents. These strips are disposable ones. Secondly, the measurement of light output by luminescent process. Hence the above statement is true.