What is the product obtained in the reaction of acetaldehyde with semicarbazide?

Given below are two statements:
Statement $I$: Cross aldol condensation between two different aldehydes will always produce four different products.
Statement $II$: When semicarbazide reacts with a mixture of benzaldehyde and acetophenone under optimum pH, it forms a condensation product with acetophenone only.
In the light of the above statements, choose the correct answer from the options given below:

Given below are two statements:
Statement $I$: $2, 6$-diethylcyclohexanone and $6$-methyl-$2$-$n$-propylcyclohexanone are metamers.
Statement $II$: $2, 2, 6, 6$-tetramethylcyclohexanone exhibits keto-enol tautomerism.

Which among the following compounds is a hemiacetal?

The product obtained as a result of the reaction between acetone and chloroform is used as:

In the given transformation,which of the following is the most appropriate reagent?