Which of the following are examples of aldol condensation ?
1.`2CH_(3)CHOoverset(dil. NaOH)to CH_(3)CHOHCH_(2)CHO` . `2CH_(3)COCH_(3)overset(dil. NaOH)to CH_(3)COCH(CH_(3))CH_(2)COCH_(3)`
3. `2HCHOoverset(dil. NaOH)to CH_(3)OH+HCOOH`
4. `C_(6)H_(5)CHO+HCHOoverset(dil. NaOH)toC_(6)H_(5)CH_(2)OH`
A. 2,3
B. 1 , 3
C. 1 , 2
D. 1,2,3
