An Ideal Carnot Engine Operating Between a Warm Reservoir of Unknown

Multiple Choice

An ideal Carnot engine operating between a warm reservoir of unknown temperature and a cold reservoir at $1.76 \mathrm {~K}$ has an efficiency of $40.0 \%$ What is the temperature of the warm reservoir?

A) 2.93 K
B) 0.0500 K
C) 106 K
D) 0.0400 K