4. two things to keep in mind when you're deciding whether to use formal or informal english are the
a. reader and the location.
b. occasion and the audience.
c. opinion and the occasion.
d. reader and the audience.

B. occasion and the audience.

Both of these factors are important in considering and keeping in mind when to decide using formal or informal audience. Occasion is as vital as the audience. To examine which people are going to read and listen to your speech must be in lined with the English type of medium you’re going to use. For instance, going a Psychological convention when you will present your dissertation paper, you must be keen to the details, jargons used and the English type with utmost criticism.  Consider the given example.