"Threw" is the past participle of the verb "to throw" - the word you are looking for is "through", which is pronounced the same way.
Anyway, to business...
A)The A isomer forms threw oxidation 1 cetone.
A = 2 ethyl 1 butene
By "cetone", do you mean "acetone"?
2-ethyl-1-butene yould give pentan-3-one and CO
2 as products - no acetone would be produced at all.
B) B and C isomers form threw oxidation 1 single acid.
B = 1 hexene
C = 2 hexene
1-hexene would give pentanoic acid and CO
2.
2-hexene would give butanoic acid and ethanoic acid as products.
Try to think of an alkene that gives only one product.
C)The isomer D form threw oxidation:1 acetone, and 1 acid.
D = 2 emthyl 2 pentene
Correct
D)The isomer E form threw oxidation: CO2, H20 and the acid 2,2 dimethylpropane
E = 3,3 dimethyl 1 butene.
By "the acid 2,2 dimethylpropane", I assume you mean "2,2-dimethylpropanoic acid". Your answer is correct.