Consider the regression model

ln⁡(demand)=β1+β2ln⁡(ownprice)+β3ln⁡(competitor′sprice)+u

How would you interpret the coefficient β2 ?

A 1% increase in my own price will lead to a -β2  % change in demand, if my competitor does not change his/her price.

A 1% increase in my own price will lead to a -β2 % change in demand, taking into account my competitor’s reaction to my price change.

A 1% increase in my own price will lead to a -β2/100  unit change in demand, taking into account my competitor’s reaction to my price change.

A 1% increase in my own price will lead to a -β2/100 unit change in demand, if my competitor does not change his/her price.