Questions

Budapest is the capital of Hungary

'Rare earth'(They are all metals)

Producer are Autotrophs as they prepare their own food and does'nt depend on others as Customers or Heterotrophs which depend on producers or Autotrophs.

Electronegativity is the tendency for an atom to attract electrons. There are general trends on the periodic table which you can use to determine the relative electronegativity for different elements, but otherwise you can also look at their valence shell and effective nuclear charge to determine their relative electronegativity.

Here from the given options, Lithium has least tendency to attract electrons and thus has a lower electronegativity.