Which of the following phrases is the best synonym for 'happy'?

The phrase 'glad' is the best synonym for 'happy' because both words express a sense of pleasure or contentment. When someone is happy, they often feel joyful or satisfied, which aligns closely with the meaning of 'glad.' In various contexts, both terms can be used interchangeably to convey a positive emotional state, indicating a feeling of delight or gratification.

The other words present different emotions and do not convey the same meaning. 'Sad' indicates unhappiness, 'angry' reflects a state of rage or frustration, and 'excited' can suggest a heightened state of enthusiasm but does not inherently relate to the calm, contented feeling that 'happy' and 'glad' share.