Question about interpretation of an answer choice : Magoosh

Last year the rate of inflation was 1.2 percent, but for the current year it has been 4 percent. We can conclude that inflation is on an upward trend and the rate will be still higher next year.

Which of the following, if true, most seriously weakens the conclusion above?

I had a question about my interpretation of (B) which reads:

Last year a dip in oil prices brought inflation temporarily below its recent stable annual level
of 4 percent.

When I read it I thought it was just restating the stimulus. "Last year a dip in oil prices brought inflation temporarily below..." well of course it did, the inflation last year was 1.2%, that is below 4%, and the 1.2% inflation rate didn't last since the current rate is 4%, hence the use of the word "temporarily"; this part of the sentence is just giving us another explanation about the stimulus and doesn't weaken the fact that there is an upward trend. Then, perhaps more importantly, my interpretation of "recent stable annual level" is that it is an describing the 4%. The most recent interest rate was 4%, and "stable annual level" describes the behavior of the rate throughout the year. This doesn't give me any indication of weakening the reasoning, which is that there is an upward trend from year to year, NOT throughout the year.

Stated differently:
The inflation rate before last year could have been 1% or it could have been 3%, and the behavior of oil prices brought it to 1.2%, temporarily, meaning only for some time, and, no matter the starting point, 1.2% is still below the "RECENT stable annual rate" of 4%.

If I am understanding correctly, I think almost everyone in the answer thread to this question interpreted the statement to mean that the inflation level went from 4% to 1.2% back up to 4%, but that implies that the inflation rate dipped, when it was the oil prices that dipped; surely they don't expect the correlation of oil and inflation to be common knowledge? Also the statement says "RECENT stable annual level" and not "stable annual level", so isn't that a logical misnomer, calling something in the past "recent"? Ex. Two years ago, the cost of corn was its recent price of $5.00. Maybe not a logical misnomer but the it is an unclear statement.

I know there's something lost in translation here and I'm trying to find it. Thank you for your help!