Questions

The given sentence is in simple present tense and states a general fact, hence the latter half of the sentence with the blank will also be in the simple present tense. Since the subject in the latter part of the sentence is singular .i.e. 'the number', the verb will be followed accordingly. Hence, option 4 is the correct answer.

Being positive is important because often a person’s attitude to their work can come across in their writing and presentation. 

Example ::

An admin plays an important role in ensuring that diaries are properly managed and that all outgoing correspondence is well written and all incoming correspondence is read and delivered to the relevant managers quickly. Administrators sometimes provide the first impression a customer has of a business, so a positive and professional outlook is needed at all times.