Which early development allowed people the ability to keep records and also express themselves creatively?

A writing system.

Explanation:

A writing system can be defined as a strategic method used by humans to visually represent the oral or verbal form of communication based on a set of standards and rule. Simply stated, a writing system is a method used to express a language through the use of letters, symbols and other marks.

It is generally considered to be an early development skill which gave people the ability to keep records and also express themselves creatively. The first writing system dates to as far back as the Bronze Age after the Neolithic Era.

According to history, the first writing system originated from Ancient Sumer, Mesopotamia around 3,100 BC and it was referred to as cuneiform. This writing system availed humans in this old era the opportunity and ability to record, store, disseminate and transmit informations from one generation to another.

silk

indigo  

rice

all the other answers are wrong

the manhattan project's indispensable man