Steel bars, each of length 3.0 m at 28°C, are to be used for constructing a rail line. If the linear expansivity of steel is 1.0 x 10^-5°C, what is the safety gap that must be left between successive bars if the highest temperature expected is 40^oC?

• A.1.2 x 10^-1cm
• B.8.4 x 10^-2cm
• C.7.2 x10^-2cm
• D.3.6 x 10^-2cm
• E.1.8 x 10^-2cm