The structure of the compound A in the following reaction sequence is

Concept:

LiBH4 is a mild and selective reducing agent, making it suitable for a wide range of functional group reductions. It is less reactive towards other functional groups than some harsher reducing agents, allowing for greater control over reactions. Some common functional groups that can be reduced by LiBH4 include carbonyl compounds (aldehydes and ketones), carboxylic acids and their derivatives, and imines.

Explanation:

• LiBH₄ is less reactive and not enough to reduce amide, it can only reduce aldehyde, ketone to its corresponding alcohol. 
• t-butyl is a bulky group so LiBH₄ is unable to reduce the group.

• After the formation of diol cyclization occurs in the presence of CF₃CO₂H and H₂O. 

Conclusion:

Hence, the intermediate A formed is cis-diol.