Final answer:
The correct answer is A) Elephant, which has the short e (/ĕ/) sound, unlike the other options that either have different vowel sounds or a long vowel sound.
Step-by-step explanation:
The best keyword for the introduction of short e (/ĕ/) out of the given options is A) Elephant. Words that contain a short e sound have a more abrupt sound compared to the long e, which sounds like it is being stretched out.
Examples of short e sounds are in the words 'slept', 'dense', and 'fell', whereas examples of long e sounds are found in 'green', 'me', and 'beam'. Note that the word 'cake' has a long a sound, 'ice' has a long i sound, and 'ball' has a short a sound; none of these words contain the short e sound we are looking for.