option vs willingness

option

noun
  • The freedom or right to choose. 

  • A contract giving the holder the right to buy or sell an asset at a set strike price; can apply to financial market transactions, or to ordinary transactions for tangible assets such as a residence or automobile. 

  • One of a set of choices that can be made. 

  • The acquiring or retention of a nationality through personal choice as a right, bypassing selective legal mechanisms for naturalization, especially in cases where a territory is transferred or passed on from one state to another. 

verb
  • To purchase an option on something. 

willingness

noun
  • The state of being willing 

How often have the words option and willingness occurred in a corpus of books? (source: Google Ngram Viewer )