Open office, simple if then function help

Hello,
A2 through A50=date
B2 through B50=Store
C2 through C50=Type( A list of categories-Food,Gas,Fun,Dinning)
D2 through D50=Spent($ spent )

F10 should pull data
I want it to search through column C and look for all the rows that say gas flag them then add up the d column of the same row to see how much i spent on gas for that month

so f10= if column c =gas then add up money spent in corresponding d column so final result will be a dollar amount spent on gas if c says food it would not be included in the total.