Which line in the table is likely to be correct for the element francium?

I can't tell from the information given, however, my periodic table lists the melting point as 27C and identifies the element as a liquid. Cesium is also shows as a liquid with a melting point of 28.7C, following the trend of decreasing melting points from lithium on down. If you are correct in the trend for the first ionization energy, then your answer will be "B."