Ag
Step 1: Silver (Ag) is often mistakenly included in questions about 3d transition metals due to its placement in group 11, similar to transition metals.
Step 2: Among the listed elements, Mn typically has the lowest melting point of the actual 3d transition metals.
Step 3: However, the inclusion of Ag, which is actually a 4d transition metal, not a 3d, and its low melting point compared to typical 3d metals, makes it the correct choice under the given options.
Step 4: Therefore, despite the potential error in categorization, Ag is the answer if included in the options for its lower melting point among the choices.
Kepler's second law (law of areas) of planetary motion leads to law of conservation of