In the compound $7-ethyl 3-nonene-2,5,8-$ tricarboxylic acid, how many atoms are in $s{p}^2-$ hybridization state?

All three carbon of three $-COOH$ are $s{p}^2$

Three oxygen, one in each $-COOH$ are $s{p}^2$

Both C-3 and C-4 carbons are $s{p}^2$