$アップル (AAPL.US)$ “Time Flies” event is set for September 15 at 10 a.m. PT/ 1 p.m. ET, where the company is expected to debut a host of new devices including a new Apple Watch and iPad, as well as a pair of over-the-ear headphones, a first for the tech giant.

オプションを購入する際には、考慮すべきことがいくつかあり、最も重要な要因の1つはDeltaです
Deltaとは何ですか？