When evaluating a scientific notation, the important thing to remember is that the more negative the exponent of 10 is, the smaller is its value. The opposite is true for positive exponents. With that, the arrangement from least to greatest is:
1.2 x 10^-5cm < 1.7x 10^-4cm < 1.9 x 10^-4cm < 1.4 x 10^-3cm
