According to Standard English conventions, the proper use of commas in this sentence is to use them around the transitional word "then" which functions as a parenthetical expression. The commas separate "then" from the rest of the sentence, making it clear that it is providing additional information to the reader. The other options either lack commas entirely or place them incorrectly, breaking the sentence's flow and making it difficult to read. Option b utilizes the commas correctly, separating "then" and maintaining the sentence's readability and proper sentence structure.

According to Standard English conventions, Option D is the correct choice for the proper use of commas in this sentence. Option D correctly uses commas to list the activities Lisa engaged in during her trip. The other options either don't separate the listed items properly with commas or place commas unnecessarily, breaking the sentence's flow and making it difficult to read.

According to Standard English conventions, the proper use of commas in this sentence is to separate the various geological formations. Option D does not include any commas in the last part of the sentence, as none are needed. The other options either add unnecessary commas or place them incorrectly, making the sentence difficult to read and understand. Option D maintains the proper sentence structure and provides clear communication of the listed formations.

According to Standard English conventions, the proper use of commas in this sentence is to place them around the transitional word "however" which functions as a parenthetical expression. The commas separate "however" from the rest of the sentence, making it clear that it is providing additional information to the reader. The other options either lack commas entirely or place them incorrectly, breaking the sentence's flow and making it difficult to read. Option B uses the commas correctly, separating "however" and maintaining the sentence's readability and proper sentence structure.

According to Standard English conventions, Option B is the correct choice for the proper use of commas in this sentence. Option B correctly uses commas to list the activities organized by the school's environmental club. The other options either don't separate the listed items properly with commas or place commas unnecessarily, breaking the sentence's flow and making it difficult to read.