Topic: Substitution, Expression, & Definition,

Best Answer Explained in Below-:

The phrase "head in the clouds" typically refers to someone who is lost in thought, daydreaming, or preoccupied with fanciful ideas and unrealistic ambitions. This expression metaphorically suggests that a person's thoughts and aspirations are elevated and detached from practical reality, akin to being up in the clouds where one cannot clearly see the ground or surroundings.

In the context of the question about a parson, which is a clergyman or minister, having their "head in the clouds" implies that they might be more focused on spiritual or lofty ideals rather than the tangible issues of everyday life. This aligns closely with option B, "a day dreamer."

The other options do not fit as well. "Proud" (A) indicates an inflated sense of self-worth but doesn't capture the essence of daydreaming. "An aviator" (C) is too literal and unrelated, while "useless" (D) carries a negative connotation that doesn't quite fit the descriptive nature of the original phrase. Hence, option B best encapsulates the meaning of the expression, making it the correct choice.