The correct answer is C. Rs. 9.
Under the Halsey Plan, the worker is paid his regular rate for all time worked, plus a bonus of 50% of the time saved. In this case, the worker worked for 8 hours and saved 2 hours. His wages are therefore 8 hours x Rs. 1/hour + 2 hours x 50% x Rs. 1/hour = Rs. 9.
Option A is incorrect because it is the regular rate of pay for 8 hours. Option B is incorrect because it is the standard time for the job. Option D is incorrect because it is the regular rate of pay for 10 hours plus a bonus of 50% of the time saved.