Model/Adminhtml/Source/PaymentCurrency.php
public function getPaymentCurrencyOptions()
    { 
        // Create the base options
        $options = [
            [
                'value' => self::BASE_CURRENCY,
                'label' => __('Use Magento default')
            ],
            [
                'value' => self::ORDER_CURRENCY,
                'label' => __('Order currency')
            ],
            [
                'value' => self::CUSTOM_CURRENCY,
                'label' => __('Custom currency')
            ],
        ];

        // Return the options as array
        return $options;
    }
public function getPaymentCurrencyOptions()
    { 
        // Create the base options
        $options = [
            [
                'value' => self::BASE_CURRENCY,
                'label' => __('Use Magento default')
            ],
            [
                'value' => self::ORDER_CURRENCY,
                'label' => __('Order currency')
            ],
            [
                'value' => self::CUSTOM_CURRENCY,
                'label' => __('Custom currency')
            ],
        ];

        // Return the options as array
        return $options;
    }
public function getPaymentCurrencyOptions ( ) { // Create the base options $ options = [ [ 'value' => self :: BASE_CURRENCY , 'label' => __ ( 'Use Magento default' ) ] , [ 'value' => self :: ORDER_CURRENCY , 'label' => __ ( 'Order currency' ) ] , [ 'value' => self :: CUSTOM_CURRENCY , 'label' => __ ( 'Custom currency' ) ] , ] ; // Return the options as array return $ options ; }
Get the payment currency options

@return array
Get the payment currency options