Final answer:
Second degree AV block, Type II is more likely to progress to complete heart block compared to the other options.
Step-by-step explanation:
In terms of heart blocks, second degree AV block, Type II is more likely to progress to complete heart block compared to the other options.
A first-degree AV block is characterized by a delay in conduction between the SA and AV nodes, but it does not typically progress to complete heart block.
Second degree AV block, Type I (Wenckebach) is characterized by a progressive lengthening of the PR interval until a QRS complex is dropped, but it usually does not progress to complete heart block.
On the other hand, second degree AV block, Type II is characterized by occasional dropped QRS complexes without the progressive lengthening of the PR interval. This type of block has a higher risk of progressing to complete heart block.