Credited with - when we mention what someone has achieved...
Credited to - when we associate one's achievement/success with a source/reason of something else...
Newton is credited with
discovering the laws of motion. -- here we talk about what is achieved.
Edison is credited with
discovering the bulb -- here we talk about what is achieved.
We had to credit much of our success to
simple good luck. -- here we talk about the source of achievement.
guess such difference is explained in MGMAT SC
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