A train travels 40 km at a uniform speed of 30 km\[{{\text{h}}^{-\text{1}}}\]. Its average speed after traveling another 40 km is 45 km \[{{\text{h}}^{-\text{1}}}\] for the whole journey. Its speed in the second half of the journey is

• A. 45kmh \[{{\text{h}}^{-\text{1}}}\]             
• B. 90kmh \[{{\text{h}}^{-\text{1}}}\]
• C. 60kmh \[{{\text{h}}^{-\text{1}}}\]             
• D. None of these