Answer:The correct answer is option (C).
Explanation:
Average speed is defined as total distance covered by the body divide by the time elapsed( passed).
[tex]\text{Average speed}=\frac{\text{Total distance}}{\text{Time Elapsed}}[/tex]
Suppose body has covered [tex]D_1[/tex] distance in [tex]T_1[/tex] first interval and after it covered [tex]D_2[/tex] distance in [tex]T_2[/tex] in second interval. So, the Average speed will be ;
[tex]\text{Average speed}=\frac{D_1+D_2}{T_1+T_2}[/tex]
Hence ,the correct answer is option (C.).