Anna is option speculator and has an option portfolio on a single stock. She thinks that there is the stock risk and that will increase substantially- more so than is reflected in option market prices.

(1) What is option Vega and does it measure?

(2) Which one is better to decrease or increase the portfolio vega?

(3) In order to change portfolio vega, what does she have to do buy or sell puts (or) buy or sell calls?