An ideal heat engine working between temperature ${\mathrm{T}}_{\mathrm{H}} \mathrm{and} {\mathrm{T}}_{\mathrm{L}}$ has efficiency $\mathrm{\eta }$. If both the temperature are raised by 100 K each, the new efficiency of heat engine will be: 

• A

  equal to $\mathrm{\eta }$

• B

  greater than $\mathrm{\eta }$

• C

  less than $\mathrm{\eta }$

• D

  greater or less than $\mathrm{\eta }$ depending upon the nature of the working substance